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1.  Imputation and subset-based association analysis across different cancer types identifies multiple independent risk loci in the TERT-CLPTM1L region on chromosome 5p15.33 
Wang, Zhaoming | Zhu, Bin | Zhang, Mingfeng | Parikh, Hemang | Jia, Jinping | Chung, Charles C. | Sampson, Joshua N. | Hoskins, Jason W. | Hutchinson, Amy | Burdette, Laurie | Ibrahim, Abdisamad | Hautman, Christopher | Raj, Preethi S. | Abnet, Christian C. | Adjei, Andrew A. | Ahlbom, Anders | Albanes, Demetrius | Allen, Naomi E. | Ambrosone, Christine B. | Aldrich, Melinda | Amiano, Pilar | Amos, Christopher | Andersson, Ulrika | Andriole, Gerald | Andrulis, Irene L. | Arici, Cecilia | Arslan, Alan A. | Austin, Melissa A. | Baris, Dalsu | Barkauskas, Donald A. | Bassig, Bryan A. | Beane Freeman, Laura E. | Berg, Christine D. | Berndt, Sonja I. | Bertazzi, Pier Alberto | Biritwum, Richard B. | Black, Amanda | Blot, William | Boeing, Heiner | Boffetta, Paolo | Bolton, Kelly | Boutron-Ruault, Marie-Christine | Bracci, Paige M. | Brennan, Paul | Brinton, Louise A. | Brotzman, Michelle | Bueno-de-Mesquita, H. Bas | Buring, Julie E. | Butler, Mary Ann | Cai, Qiuyin | Cancel-Tassin, Geraldine | Canzian, Federico | Cao, Guangwen | Caporaso, Neil E. | Carrato, Alfredo | Carreon, Tania | Carta, Angela | Chang, Gee-Chen | Chang, I-Shou | Chang-Claude, Jenny | Che, Xu | Chen, Chien-Jen | Chen, Chih-Yi | Chen, Chung-Hsing | Chen, Constance | Chen, Kuan-Yu | Chen, Yuh-Min | Chokkalingam, Anand P. | Chu, Lisa W. | Clavel-Chapelon, Francoise | Colditz, Graham A. | Colt, Joanne S. | Conti, David | Cook, Michael B. | Cortessis, Victoria K. | Crawford, E. David | Cussenot, Olivier | Davis, Faith G. | De Vivo, Immaculata | Deng, Xiang | Ding, Ti | Dinney, Colin P. | Di Stefano, Anna Luisa | Diver, W. Ryan | Duell, Eric J. | Elena, Joanne W. | Fan, Jin-Hu | Feigelson, Heather Spencer | Feychting, Maria | Figueroa, Jonine D. | Flanagan, Adrienne M. | Fraumeni, Joseph F. | Freedman, Neal D. | Fridley, Brooke L. | Fuchs, Charles S. | Gago-Dominguez, Manuela | Gallinger, Steven | Gao, Yu-Tang | Gapstur, Susan M. | Garcia-Closas, Montserrat | Garcia-Closas, Reina | Gastier-Foster, Julie M. | Gaziano, J. Michael | Gerhard, Daniela S. | Giffen, Carol A. | Giles, Graham G. | Gillanders, Elizabeth M. | Giovannucci, Edward L. | Goggins, Michael | Gokgoz, Nalan | Goldstein, Alisa M. | Gonzalez, Carlos | Gorlick, Richard | Greene, Mark H. | Gross, Myron | Grossman, H. Barton | Grubb, Robert | Gu, Jian | Guan, Peng | Haiman, Christopher A. | Hallmans, Goran | Hankinson, Susan E. | Harris, Curtis C. | Hartge, Patricia | Hattinger, Claudia | Hayes, Richard B. | He, Qincheng | Helman, Lee | Henderson, Brian E. | Henriksson, Roger | Hoffman-Bolton, Judith | Hohensee, Chancellor | Holly, Elizabeth A. | Hong, Yun-Chul | Hoover, Robert N. | Hosgood, H. Dean | Hsiao, Chin-Fu | Hsing, Ann W. | Hsiung, Chao Agnes | Hu, Nan | Hu, Wei | Hu, Zhibin | Huang, Ming-Shyan | Hunter, David J. | Inskip, Peter D. | Ito, Hidemi | Jacobs, Eric J. | Jacobs, Kevin B. | Jenab, Mazda | Ji, Bu-Tian | Johansen, Christoffer | Johansson, Mattias | Johnson, Alison | Kaaks, Rudolf | Kamat, Ashish M. | Kamineni, Aruna | Karagas, Margaret | Khanna, Chand | Khaw, Kay-Tee | Kim, Christopher | Kim, In-Sam | Kim, Jin Hee | Kim, Yeul Hong | Kim, Young-Chul | Kim, Young Tae | Kang, Chang Hyun | Jung, Yoo Jin | Kitahara, Cari M. | Klein, Alison P. | Klein, Robert | Kogevinas, Manolis | Koh, Woon-Puay | Kohno, Takashi | Kolonel, Laurence N. | Kooperberg, Charles | Kratz, Christian P. | Krogh, Vittorio | Kunitoh, Hideo | Kurtz, Robert C. | Kurucu, Nilgun | Lan, Qing | Lathrop, Mark | Lau, Ching C. | Lecanda, Fernando | Lee, Kyoung-Mu | Lee, Maxwell P. | Le Marchand, Loic | Lerner, Seth P. | Li, Donghui | Liao, Linda M. | Lim, Wei-Yen | Lin, Dongxin | Lin, Jie | Lindstrom, Sara | Linet, Martha S. | Lissowska, Jolanta | Liu, Jianjun | Ljungberg, Börje | Lloreta, Josep | Lu, Daru | Ma, Jing | Malats, Nuria | Mannisto, Satu | Marina, Neyssa | Mastrangelo, Giuseppe | Matsuo, Keitaro | McGlynn, Katherine A. | McKean-Cowdin, Roberta | McNeill, Lorna H. | McWilliams, Robert R. | Melin, Beatrice S. | Meltzer, Paul S. | Mensah, James E. | Miao, Xiaoping | Michaud, Dominique S. | Mondul, Alison M. | Moore, Lee E. | Muir, Kenneth | Niwa, Shelley | Olson, Sara H. | Orr, Nick | Panico, Salvatore | Park, Jae Yong | Patel, Alpa V. | Patino-Garcia, Ana | Pavanello, Sofia | Peeters, Petra H. M. | Peplonska, Beata | Peters, Ulrike | Petersen, Gloria M. | Picci, Piero | Pike, Malcolm C. | Porru, Stefano | Prescott, Jennifer | Pu, Xia | Purdue, Mark P. | Qiao, You-Lin | Rajaraman, Preetha | Riboli, Elio | Risch, Harvey A. | Rodabough, Rebecca J. | Rothman, Nathaniel | Ruder, Avima M. | Ryu, Jeong-Seon | Sanson, Marc | Schned, Alan | Schumacher, Fredrick R. | Schwartz, Ann G. | Schwartz, Kendra L. | Schwenn, Molly | Scotlandi, Katia | Seow, Adeline | Serra, Consol | Serra, Massimo | Sesso, Howard D. | Severi, Gianluca | Shen, Hongbing | Shen, Min | Shete, Sanjay | Shiraishi, Kouya | Shu, Xiao-Ou | Siddiq, Afshan | Sierrasesumaga, Luis | Sierri, Sabina | Loon Sihoe, Alan Dart | Silverman, Debra T. | Simon, Matthias | Southey, Melissa C. | Spector, Logan | Spitz, Margaret | Stampfer, Meir | Stattin, Par | Stern, Mariana C. | Stevens, Victoria L. | Stolzenberg-Solomon, Rachael Z. | Stram, Daniel O. | Strom, Sara S. | Su, Wu-Chou | Sund, Malin | Sung, Sook Whan | Swerdlow, Anthony | Tan, Wen | Tanaka, Hideo | Tang, Wei | Tang, Ze-Zhang | Tardon, Adonina | Tay, Evelyn | Taylor, Philip R. | Tettey, Yao | Thomas, David M. | Tirabosco, Roberto | Tjonneland, Anne | Tobias, Geoffrey S. | Toro, Jorge R. | Travis, Ruth C. | Trichopoulos, Dimitrios | Troisi, Rebecca | Truelove, Ann | Tsai, Ying-Huang | Tucker, Margaret A. | Tumino, Rosario | Van Den Berg, David | Van Den Eeden, Stephen K. | Vermeulen, Roel | Vineis, Paolo | Visvanathan, Kala | Vogel, Ulla | Wang, Chaoyu | Wang, Chengfeng | Wang, Junwen | Wang, Sophia S. | Weiderpass, Elisabete | Weinstein, Stephanie J. | Wentzensen, Nicolas | Wheeler, William | White, Emily | Wiencke, John K. | Wolk, Alicja | Wolpin, Brian M. | Wong, Maria Pik | Wrensch, Margaret | Wu, Chen | Wu, Tangchun | Wu, Xifeng | Wu, Yi-Long | Wunder, Jay S. | Xiang, Yong-Bing | Xu, Jun | Yang, Hannah P. | Yang, Pan-Chyr | Yatabe, Yasushi | Ye, Yuanqing | Yeboah, Edward D. | Yin, Zhihua | Ying, Chen | Yu, Chong-Jen | Yu, Kai | Yuan, Jian-Min | Zanetti, Krista A. | Zeleniuch-Jacquotte, Anne | Zheng, Wei | Zhou, Baosen | Mirabello, Lisa | Savage, Sharon A. | Kraft, Peter | Chanock, Stephen J. | Yeager, Meredith | Landi, Maria Terese | Shi, Jianxin | Chatterjee, Nilanjan | Amundadottir, Laufey T.
Human Molecular Genetics  2014;23(24):6616-6633.
Genome-wide association studies (GWAS) have mapped risk alleles for at least 10 distinct cancers to a small region of 63 000 bp on chromosome 5p15.33. This region harbors the TERT and CLPTM1L genes; the former encodes the catalytic subunit of telomerase reverse transcriptase and the latter may play a role in apoptosis. To investigate further the genetic architecture of common susceptibility alleles in this region, we conducted an agnostic subset-based meta-analysis (association analysis based on subsets) across six distinct cancers in 34 248 cases and 45 036 controls. Based on sequential conditional analysis, we identified as many as six independent risk loci marked by common single-nucleotide polymorphisms: five in the TERT gene (Region 1: rs7726159, P = 2.10 × 10−39; Region 3: rs2853677, P = 3.30 × 10−36 and PConditional = 2.36 × 10−8; Region 4: rs2736098, P = 3.87 × 10−12 and PConditional = 5.19 × 10−6, Region 5: rs13172201, P = 0.041 and PConditional = 2.04 × 10−6; and Region 6: rs10069690, P = 7.49 × 10−15 and PConditional = 5.35 × 10−7) and one in the neighboring CLPTM1L gene (Region 2: rs451360; P = 1.90 × 10−18 and PConditional = 7.06 × 10−16). Between three and five cancers mapped to each independent locus with both risk-enhancing and protective effects. Allele-specific effects on DNA methylation were seen for a subset of risk loci, indicating that methylation and subsequent effects on gene expression may contribute to the biology of risk variants on 5p15.33. Our results provide strong support for extensive pleiotropy across this region of 5p15.33, to an extent not previously observed in other cancer susceptibility loci.
doi:10.1093/hmg/ddu363
PMCID: PMC4240198  PMID: 25027329
2.  Ambient Particulate Matter Air Pollution Exposure and Mortality in the NIH-AARP Diet and Health Cohort 
Environmental Health Perspectives  2015;124(4):484-490.
Background:
Outdoor fine particulate matter (≤ 2.5 μm; PM2.5) has been identified as a global health threat, but the number of large U.S. prospective cohort studies with individual participant data remains limited, especially at lower recent exposures.
Objectives:
We aimed to test the relationship between long-term exposure PM2.5 and death risk from all nonaccidental causes, cardiovascular (CVD), and respiratory diseases in 517,041 men and women enrolled in the National Institutes of Health-AARP cohort.
Methods:
Individual participant data were linked with residence PM2.5 exposure estimates across the continental United States for a 2000–2009 follow-up period when matching census tract–level PM2.5 exposure data were available. Participants enrolled ranged from 50 to 71 years of age, residing in six U.S. states and two cities. Cox proportional hazard models yielded hazard ratio (HR) estimates per 10 μg/m3 of PM2.5 exposure.
Results:
PM2.5 exposure was significantly associated with total mortality (HR = 1.03; 95% CI: 1.00, 1.05) and CVD mortality (HR = 1.10; 95% CI: 1.05, 1.15), but the association with respiratory mortality was not statistically significant (HR = 1.05; 95% CI: 0.98, 1.13). A significant association was found with respiratory mortality only among never smokers (HR = 1.27; 95% CI: 1.03, 1.56). Associations with 10-μg/m3 PM2.5 exposures in yearly participant residential annual mean, or in metropolitan area-wide mean, were consistent with baseline exposure model results. Associations with PM2.5 were similar when adjusted for ozone exposures. Analyses of California residents alone also yielded statistically significant PM2.5 mortality HRs for total and CVD mortality.
Conclusions:
Long-term exposure to PM2.5 air pollution was associated with an increased risk of total and CVD mortality, providing an independent test of the PM2.5–mortality relationship in a new large U.S. prospective cohort experiencing lower post-2000 PM2.5 exposure levels.
Citation:
Thurston GD, Ahn J, Cromar KR, Shao Y, Reynolds HR, Jerrett M, Lim CC, Shanley R, Park Y, Hayes RB. 2016. Ambient particulate matter air pollution exposure and mortality in the NIH-AARP Diet and Health cohort. Environ Health Perspect 124:484–490; http://dx.doi.org/10.1289/ehp.1509676
doi:10.1289/ehp.1509676
PMCID: PMC4829984  PMID: 26370657
3.  Fecal Microbiota, Fecal Metabolome, and Colorectal Cancer Interrelations 
PLoS ONE  2016;11(3):e0152126.
Background and Aims
Investigation of microbe-metabolite relationships in the gut is needed to understand and potentially reduce colorectal cancer (CRC) risk.
Methods
Microbiota and metabolomics profiling were performed on lyophilized feces from 42 CRC cases and 89 matched controls. Multivariable logistic regression was used to identify statistically independent associations with CRC. First principal coordinate-component pair (PCo1-PC1) and false discovery rate (0.05)-corrected P-values were calculated for 116,000 Pearson correlations between 530 metabolites and 220 microbes in a sex*case/control meta-analysis.
Results
Overall microbe-metabolite PCo1-PC1 was more strongly correlated in cases than in controls (Rho 0.606 vs 0.201, P = 0.01). CRC was independently associated with lower levels of Clostridia, Lachnospiraceae, p-aminobenzoate and conjugated linoleate, and with higher levels of Fusobacterium, Porphyromonas, p-hydroxy-benzaldehyde, and palmitoyl-sphingomyelin. Through postulated effects on cell shedding (palmitoyl-sphingomyelin), inflammation (conjugated linoleate), and innate immunity (p-aminobenzoate), metabolites mediated the CRC association with Fusobacterium and Porphyromonas by 29% and 34%, respectively. Overall, palmitoyl-sphingomyelin correlated directly with abundances of Enterobacteriaceae (Gammaproteobacteria), three Actinobacteria and five Firmicutes. Only Parabacteroides correlated inversely with palmitoyl-sphingomyelin. Other lipids correlated inversely with Alcaligenaceae (Betaproteobacteria). Six Bonferroni-significant correlations were found, including low indolepropionate and threnoylvaline with Actinobacteria and high erythronate and an uncharacterized metabolite with Enterobacteriaceae.
Conclusions
Feces from CRC cases had very strong microbe-metabolite correlations that were predominated by Enterobacteriaceae and Actinobacteria. Metabolites mediated a direct CRC association with Fusobacterium and Porphyromonas, but not an inverse association with Clostridia and Lachnospiraceae. This study identifies complex microbe-metabolite networks that may provide insights on neoplasia and targets for intervention.
doi:10.1371/journal.pone.0152126
PMCID: PMC4807824  PMID: 27015276
4.  Association of aspirin and non-steroidal anti-inflammatory drug use with risk of colorectal cancer according to genetic variants 
JAMA  2015;313(11):1133-1142.
Importance
Use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) is associated with lower risk of colorectal cancer. Prior studies examining a potential differential relationship of aspirin and NSAIDs with colorectal cancer risk according to genetic factors have been limited to analyses of candidate genes or pathways.
Objective
To comprehensively identify common genetic markers that characterize individuals who may obtain differential benefit from aspirin and/or NSAID chemoprevention, we tested gene by environment (G X E) interactions between regular use of aspirin and/or NSAIDs and single nucleotide polymorphisms (SNPs) across the genome in relation to risk of colorectal cancer.
Design
Case-control study using the Colon Cancer Family Registry (CCFR) and the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) that enrolled cases of colorectal cancer ascertained between 1976 and 2011 and matched controls. Odds ratios (ORs) of colorectal cancer and 95% confidence intervals (95% CIs) were estimated using conventional logistic regression analysis and case-only interaction analysis, after adjusting for age, sex, center, the first three principal components to account for population structure, and known colorectal cancer risk factors. For all genome-wide analyses, a two-sided p-value<5.0×10-8, which yields a genome-wide significance level of 0.05, was considered statistically significant.
Setting
10 observational studies (5 case-control and 5 cohort studies) that were initiated between 1976 and 2003 across the U.S., Canada, Australia and Germany.
Participants
8,634 colorectal cancer cases and 8,553 controls of European descent.
Exposures
Genome-wide SNP data generated from genome-wide association scans and imputation to HapMap II, as well as information on regular use of aspirin and/or NSAIDs and other colorectal cancer risk factors collected using in-person interviews and/or structured questionnaires.
Main Outcomes and Measures
Colorectal cancer
Results
Regular use of aspirin and/or NSAIDs was associated with lower risk of colorectal cancer (OR=0.69; 95% CI=0.64-0.74; P=6.2×10-28) compared to non-regular use. In the conventional logistic regression analysis, the SNP rs2965667 at chromosome 12p12.3 near the microsomal glutathione S-transferase 1 (MGST1) gene showed a genome-wide significant interaction with aspirin and/or NSAID use (P for interaction=4.6×10-9). Compared to non-regular use, regular use of aspirin and/or NSAIDs was associated with a lower risk of colorectal cancer among individuals with rs2965667-TT genotype (OR=0.66; 95% CI=0.61-0.70; P=7.7×10-33), but a higher risk among those with much less common (4%) TA or AA genotypes (OR=1.89; 95% CI=1.27-2.81; P=0.002). In case-only interaction analysis, the SNP rs16973225 at chromosome 15q25.2 near the interleukin 16 (IL16) gene showed a genome-wide significant interaction with aspirin and/or NSAID use (P for interaction=8.2×10-9). Compared to non-regular use, regular use of aspirin and/or NSAIDs was associated with a lower risk of colorectal cancer among individuals with rs16973225-AA genotype (OR=0.66; 95% CI=0.62-0.71; P=1.9×10-30), but was not associated with risk of colorectal cancer among those with less common (9%) AC or CC genotypes (OR=0.97; 95% CI=0.78-1.20; P=0.76).
CONCLUSIONS AND RELEVANCE
In this genome-wide investigation of G X E interactions, use of aspirin and/or NSAIDs was associated with lower risk of colorectal cancer, and the association of these medications with colorectal cancer risk differed according to genetic variation at two SNPs at chromosomes 12 and 15. Validation of these findings in additional populations may facilitate targeted colorectal cancer prevention strategies.
doi:10.1001/jama.2015.1815
PMCID: PMC4382867  PMID: 25781442
5.  Perceptions and Attitudes towards Medical Research in the United Arab Emirates: Results from the Abu Dhabi Cohort Study (ADCS) Focus Group Discussions 
PLoS ONE  2016;11(3):e0149609.
Background
In developing medical research, particularly in regions where medical research is largely unfamiliar, it is important to understand public perceptions and attitudes towards medical research. In preparation for starting the first cohort study in the United Arab Emirates, the Abu Dhabi Cohort Study (ADCS), we sought to understand how we could improve the quality of the research process for participants and increase public trust and awareness of research.
Methods
We conducted six focus groups (FG), consisting of Emirati men and women aged above 18 years to resemble the target population for the ADCS. Sampling was purposive and convenient. Data collection was an iterative process until saturation was reached with no new themes identified. Text from each FG was analyzed separately by identifying emerging issues and organizing related concepts into categories or themes. A coding tree was developed, consisting of the main concepts, themes, subthemes and corresponding quotes. Both themes and main ideas were identified using inductive analysis.
Results
Forty-two participants enrolled at 3 academic centers (New York University Abu Dhabi, UAE University, Zayed University) and the Abu Dhabi blood bank. Focus group participants described lack of awareness of research as a challenge to participation in clinical research studies. Altruism, personal relevance of the research, and the use of role models were commonly identified motivators. Participants were generally satisfied with the informed consent process for the ADCS, but would be disappointed if not provided test results or study outcomes. Fear of a breach in confidentiality was a frequently expressed concern.
Conclusions
Participants join research studies for varied, complex reasons, notably altruism and personal relevance. Based on these insights, we propose specific actions to enhance participant recruitment, retention and satisfaction in the ADCS. We identified opportunities to improve the research experience through improved study materials and communication to participants and the broader community.
doi:10.1371/journal.pone.0149609
PMCID: PMC4778844  PMID: 26943636
6.  Risk factors for head and neck cancer in young adults: a pooled analysis in the INHANCE consortium 
Background: Increasing incidence of head and neck cancer (HNC) in young adults has been reported. We aimed to compare the role of major risk factors and family history of cancer in HNC in young adults and older patients.
Methods: We pooled data from 25 case-control studies and conducted separate analyses for adults ≤45 years old (‘young adults’, 2010 cases and 4042 controls) and >45 years old (‘older adults’, 17 700 cases and 22 704 controls). Using logistic regression with studies treated as random effects, we estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs).
Results: The young group of cases had a higher proportion of oral tongue cancer (16.0% in women; 11.0% in men) and unspecified oral cavity / oropharynx cancer (16.2%; 11.1%) and a lower proportion of larynx cancer (12.1%; 16.6%) than older adult cases. The proportions of never smokers or never drinkers among female cases were higher than among male cases in both age groups. Positive associations with HNC and duration or pack-years of smoking and drinking were similar across age groups. However, the attributable fractions (AFs) for smoking and drinking were lower in young when compared with older adults (AFs for smoking in young women, older women, young men and older men, respectively, = 19.9% (95% CI = 9.8%, 27.9%), 48.9% (46.6%, 50.8%), 46.2% (38.5%, 52.5%), 64.3% (62.2%, 66.4%); AFs for drinking = 5.3% (−11.2%, 18.0%), 20.0% (14.5%, 25.0%), 21.5% (5.0%, 34.9%) and 50.4% (46.1%, 54.3%). A family history of early-onset cancer was associated with HNC risk in the young [OR = 2.27 (95% CI = 1.26, 4.10)], but not in the older adults [OR = 1.10 (0.91, 1.31)]. The attributable fraction for family history of early-onset cancer was 23.2% (8.60% to 31.4%) in young compared with 2.20% (−2.41%, 5.80%) in older adults.
Conclusions: Differences in HNC aetiology according to age group may exist. The lower AF of cigarette smoking and alcohol drinking in young adults may be due to the reduced length of exposure due to the lower age. Other characteristics, such as those that are inherited, may play a more important role in HNC in young adults compared with older adults.
doi:10.1093/ije/dyu255
PMCID: PMC4339764  PMID: 25613428
Head and neck neoplasms; adult; smoking; alcohol drinking; diet
7.  Red meat intake, NAT2, and risk of colorectal cancer: A pooled analysis of 11 studies 
Background
Red meat intake has been associated with risk of colorectal cancer (CRC), potentially mediated through heterocyclic amines. The metabolic efficiency of N-acetyltransferase 2 (NAT2) required for the metabolic activation of such amines is influenced by genetic variation. The interaction between red meat intake, NAT2 genotype, and CRC has been inconsistently reported.
Methods
We used pooled individual-level data from the Colon Cancer Family Registry (CCFR) and the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO). Red meat intake was collected by each study. We inferred NAT2 phenotype based on polymorphism at rs1495741, highly predictive of enzyme activity. Interaction was assessed using multiplicative interaction terms in multivariate-adjusted models.
Results
From 11 studies, 8,290 CRC cases and 9,115 controls were included. The highest quartile of red meat intake was associated with increased risk of CRC compared to the lowest quartile (OR 1.41, 95%CI 1.29 – 1.55). However, a significant association was observed only for studies with retrospective diet data, not for studies with diet prospectively assessed before cancer diagnosis. Combining all studies, high red meat intake was similarly associated with CRC in those with a rapid/intermediate NAT2 genotype (OR 1.38, 95%CI 1.20 – 1.59) as with a slow genotype (OR 1.43, 95%CI 1.28 – 1.61) (p- interaction=0.9).
Conclusion
We found that high red meat intake was associated with increased risk of CRC only from retrospective case-control studies and not modified by NAT2 enzyme activity.
Impact
Our results suggest no interaction between NAT2 genotype and red-meat intake in mediating risk of CRC.
doi:10.1158/1055-9965.EPI-14-0897
PMCID: PMC4294960  PMID: 25342387
8.  Association of Obesity with cardiovascular disease mortality in the PLCO trial 
Preventive medicine  2013;57(1):60-64.
Background
Obesity is a risk factor for cardiovascular disease (CVD) mortality, but the association between obesity and specific causes of CVD mortality are still under investigation.
Method
We prospectively examined body-mass index (BMI) in relation to CVD-specific causes of death in approximately 86,000 US men and women in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, followed for up to 13 years. BMI was calculated from self-reported weight and height at baseline. Hazard ratios (HRs) were calculated overall and stratified by sex, smoking status, and educational level.
Result
Overweight non-obese participants (BMI: 25.0–29.9) were not at excess risk for CVD mortality (HR and CIs are 1.02 [0.92–1.13], compared to participants of normal BMI (18.5–24.9). Excess CVD mortality was observed for participants of BMI 30.0–34.9 (HR and CIs: 1.29 [1.13–1.48], BMI 35.0–39.9 (HR and CIs: 1.87 [1.51–2.32]) and BMI 40.0+ (HR and CIs: 2.21 [1.57–3.21]) (p<0.001 for trend). BMI was unrelated to mortality due to stroke. The observed association of BMI with CVD was independent of gender, smoking status and educational level.
Conclusion
Obesity is associated with increased mortality due to CVD.
doi:10.1016/j.ypmed.2013.04.014
PMCID: PMC3674167  PMID: 23632233
9.  No evidence of gene-calcium interactions from genome-wide analysis of colorectal cancer risk 
Background
Calcium intake may reduce risk of colorectal cancer (CRC), but the mechanisms remain unclear. Studies of interaction between calcium intake and single nucleotide polymorphisms (SNPs) in calcium-related pathways have yielded inconsistent results.
Methods
To identify gene-calcium interactions, we tested interactions between ~2.7 million SNPs across the genome with self-reported calcium intake (from dietary or supplemental sources) in 9,006 CRC cases and 9,503 controls of European ancestry. To test for multiplicative interactions, we used multivariable logistic regression and defined statistical significance using the conventional genome-wide α=5E-08.
Results
After accounting for multiple comparisons, there were no statistically significant SNP-interactions with total, dietary, or supplemental calcium intake.
Conclusions
We found no evidence of SNP-interactions with calcium intake for CRC risk in a large population of 18,509 individuals.
Impact
These results suggest that in genome-wide analysis common genetic variants do not strongly modify the association between calcium intake and CRC in European populations.
doi:10.1158/1055-9965.EPI-14-0893
PMCID: PMC4257872  PMID: 25192705
10.  Fecal metabolomics: assay performance and association with colorectal cancer 
Carcinogenesis  2014;35(9):2089-2096.
Summary
Of 1043 molecules in feces, 26 were increased and 15 were decreased in CRC patients. Because fecal metabolites vary over time, very large studies with prediagnostic specimens will be needed to reliably define molecular pathways that affect colorectal carcinogenesis.
Metabolomic analysis of feces may provide insights on colorectal cancer (CRC) if assay performance is satisfactory. In lyophilized feces from 48 CRC cases, 102 matched controls, and 48 masked quality control specimens, 1043 small molecules were detected with a commercial platform. Assay reproducibility was good for 527 metabolites [technical intraclass correlation coefficient (ICC) >0.7 in quality control specimens], but reproducibility in 6-month paired specimens was lower for the majority of metabolites (within-subject ICC ≤0.5). In the CRC cases and controls, significant differences (false discovery rate ≤0.10) were found for 41 of 1043 fecal metabolites. Direct cancer association was found with three fecal heme-related molecules [covariate-adjusted 90th versus 10th percentile odds ratio (OR) = 17–345], 18 peptides/amino acids (OR = 3–14), palmitoyl-sphingomyelin (OR = 14), mandelate (OR = 3) and p-hydroxy-benzaldehyde (OR = 4). Conversely, cancer association was inverse with acetaminophen metabolites (OR <0.1), tocopherols (OR = 0.3), sitostanol (OR = 0.2), 3-dehydrocarnitine (OR = 0.4), pterin (OR = 0.3), conjugated-linoleate-18-2N7 (OR = 0.2), N-2-furoyl-glycine (OR = 0.3) and p-aminobenzoate (PABA, OR = 0.2). Correlations suggested an independent role for palmitoyl-sphingomyelin and a central role for PABA (which was stable over 6 months, within-subject ICC 0.67) modulated by p-hydroxy-benzaldehyde. Power calculations based on ICCs indicate that only 45% of metabolites with a true relative risk 5.0 would be found in prospectively collected, prediagnostic specimens from 500 cases and 500 controls. Thus, because fecal metabolites vary over time, very large studies will be needed to reliably detect associations of many metabolites that potentially contribute to CRC.
doi:10.1093/carcin/bgu131
PMCID: PMC4146421  PMID: 25037050
11.  Gene-environment interaction involving recently identified colorectal cancer susceptibility loci 
BACKGROUND
Genome-wide association studies have identified several single nucleotide polymorphisms (SNPs) that are associated with risk of colorectal cancer (CRC). Prior research has evaluated the presence of gene-environment interaction involving the first 10 identified susceptibility loci, but little work has been conducted on interaction involving SNPs at recently identified susceptibility loci, including: rs10911251, rs6691170, rs6687758, rs11903757, rs10936599, rs647161, rs1321311, rs719725, rs1665650, rs3824999, rs7136702, rs11169552, rs59336, rs3217810, rs4925386, and rs2423279.
METHODS
Data on 9160 cases and 9280 controls from the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) and Colon Cancer Family Registry (CCFR) were used to evaluate the presence of interaction involving the above-listed SNPs and sex, body mass index (BMI), alcohol consumption, smoking, aspirin use, post-menopausal hormone (PMH) use, as well as intake of dietary calcium, dietary fiber, dietary folate, red meat, processed meat, fruit, and vegetables. Interaction was evaluated using a fixed-effects meta-analysis of an efficient Empirical Bayes estimator, and permutation was used to account for multiple comparisons.
RESULTS
None of the permutation-adjusted p-values reached statistical significance.
CONCLUSIONS
The associations between recently identified genetic susceptibility loci and CRC are not strongly modified by sex, BMI, alcohol, smoking, aspirin, PMH use, and various dietary factors.
IMPACT
Results suggest no evidence of strong gene-environment interactions involving the recently identified 16 susceptibility loci for CRC taken one at a time.
doi:10.1158/1055-9965.EPI-14-0062
PMCID: PMC4209726  PMID: 24994789
Colorectal Cancer; Gene-Environment Interaction; Polymorphism; Single Nucleotide; Genetic Predisposition to Disease; Diet
12.  Prediagnostic Serum Organochlorine Concentrations and Metastatic Prostate Cancer: A Nested Case–Control Study in the Norwegian Janus Serum Bank Cohort 
Environmental Health Perspectives  2015;123(9):867-872.
Background
Organochlorine (OC) insecticides and polychlorinated biphenyls (PCBs) have been shown to have estrogenic, antiestrogenic, or antiandrogenic properties; as a result, the impact of exposure to these compounds and risk of hormonal cancers, such as prostate cancer, is a concern.
Objectives
We conducted a nested case–control study, using prospectively collected serum, to estimate associations between OC exposures and metastatic prostate cancer in a population-based cohort from Norway.
Methods
Sera from 150 cases and 314 controls matched on date of blood draw, age at blood draw, and region was used to determine concentrations of 11 OC pesticide metabolites and 34 PCB congeners. Odds ratios (ORs) and 95% confidence intervals (95% CIs) for quartiles of lipid-corrected metabolite levels were calculated using conditional logistic regression.
Results
Metastatic prostate cancer was two times as likely among men with serum concentrations of oxychlordane in the highest quartile compared with those in the lowest quartile (OR = 2.03; 95% CI: 1.03, 4.03; p-trend 0.05). Elevated but nonsignificant ORs were estimated for the highest versus lowest quartile of heptachlor epoxide, HCB, and mirex, although these exposures were correlated with oxychlordane. Findings for specific PCB congeners showed a significant inverse association between natural log–transformed lipid-adjusted PCB 44 and metastatic prostate cancer (OR = 0.74; 95% CI: 0.56, 0.97; p-trend = 0.02).
Conclusions
Our study highlights the importance of estimating associations with specific OC chemicals and suggests a possible role of OC insecticides and PCBs in the etiology of metastatic prostate cancer.
Citation
Koutros S, Langseth H, Grimsrud TK, Barr DB, Vermeulen R, Portengen L, Wacholder S, Beane Freeman LE, Blair A, Hayes RB, Rothman N, Engel LS. 2015. Prediagnostic serum organochlorine concentrations and metastatic prostate cancer: a nested case–control study in the Norwegian Janus Serum Bank cohort. Environ Health Perspect 123:867–872; http://dx.doi.org/10.1289/ehp.1408245
doi:10.1289/ehp.1408245
PMCID: PMC4559951  PMID: 25734605
13.  Association between Arsenic Exposure from Drinking Water and Longitudinal Change in Blood Pressure among HEALS Cohort Participants 
Environmental Health Perspectives  2015;123(8):806-812.
Background
Cross-sectional studies have shown associations between arsenic exposure and prevalence of high blood pressure; however, studies examining the relationship of arsenic exposure with longitudinal changes in blood pressure are lacking.
Method
We evaluated associations of arsenic exposure in relation to longitudinal change in blood pressure in 10,853 participants in the Health Effects of Arsenic Longitudinal Study (HEALS). Arsenic was measured in well water and in urine samples at baseline and in urine samples every 2 years after baseline. Mixed-effect models were used to estimate the association of baseline well and urinary creatinine-adjusted arsenic with annual change in blood pressure during follow-up (median, 6.7 years).
Result
In the HEALS population, the median water arsenic concentration at baseline was 62 μg/L. Individuals in the highest quartile of baseline water arsenic or urinary creatinine-adjusted arsenic had a greater annual increase in systolic blood pressure compared with those in the reference group (β = 0.48 mmHg/year; 95% CI: 0.35, 0.61, and β = 0.43 mmHg/year; 95% CI: 0.29, 0.56 for water arsenic and urinary creatinine-adjusted arsenic, respectively) in fully adjusted models. Likewise, individuals in the highest quartile of baseline arsenic exposure had a greater annual increase in diastolic blood pressure for water arsenic and urinary creatinine-adjusted arsenic, (β = 0.39 mmHg/year; 95% CI: 0.30, 0.49, and β = 0.45 mmHg/year; 95% CI: 0.36, 0.55, respectively) compared with those in the lowest quartile.
Conclusion
Our findings suggest that long-term arsenic exposure may accelerate age-related increases in blood pressure. These findings may help explain associations between arsenic exposure and cardiovascular disease.
Citation
Jiang J, Liu M, Parvez F, Wang B, Wu F, Eunus M, Bangalore S, Newman JD, Ahmed A, Islam T, Rakibuz-Zaman M, Hasan R, Sarwar G, Levy D, Slavkovich V, Argos M, Scannell Bryan M, Farzan SF, Hayes RB, Graziano JH, Ahsan H, Chen Y. 2015. Association between arsenic exposure from drinking water and longitudinal change in blood pressure among HEALS cohort participants. Environ Health Perspect 123:806–812; http://dx.doi.org/10.1289/ehp.1409004
doi:10.1289/ehp.1409004
PMCID: PMC4529016  PMID: 25816368
14.  Estimating the heritability of colorectal cancer 
Human Molecular Genetics  2014;23(14):3898-3905.
A sizable fraction of colorectal cancer (CRC) is expected to be explained by heritable factors, with heritability estimates ranging from 12 to 35% twin and family studies. Genome-wide association studies (GWAS) have successfully identified a number of common single-nucleotide polymorphisms (SNPs) associated with CRC risk. Although it has been shown that these CRC susceptibility SNPs only explain a small proportion of the genetic risk, it is not clear how much of the heritability these SNPs explain and how much is left to be detected by other, yet to be identified, common SNPs. Therefore, we estimated the heritability of CRC under different scenarios using Genome-Wide Complex Trait Analysis in the Genetics and Epidemiology of Colorectal Cancer Consortium including 8025 cases and 10 814 controls. We estimated that the heritability explained by known common CRC SNPs identified in GWAS was 0.65% (95% CI:0.3–1%; P = 1.11 × 10−16), whereas the heritability explained by all common SNPs was at least 7.42% (95% CI: 4.71–10.12%; P = 8.13 × 10−8), suggesting that many common variants associated with CRC risk remain to be detected. Comparing the heritability explained by the common variants with that from twin and family studies, a fraction of the heritability may be explained by other genetic variants, such as rare variants. In addition, our analysis showed that the gene × smoking interaction explained a significant proportion of the CRC variance (P = 1.26 × 10−2). In summary, our results suggest that known CRC SNPs only explain a small proportion of the heritability and more common SNPs have yet to be identified.
doi:10.1093/hmg/ddu087
PMCID: PMC4065150  PMID: 24562164
15.  Methodological Considerations in Estimation of Phenotype Heritability Using Genome-Wide SNP Data, Illustrated by an Analysis of the Heritability of Height in a Large Sample of African Ancestry Adults 
PLoS ONE  2015;10(6):e0131106.
Height has an extremely polygenic pattern of inheritance. Genome-wide association studies (GWAS) have revealed hundreds of common variants that are associated with human height at genome-wide levels of significance. However, only a small fraction of phenotypic variation can be explained by the aggregate of these common variants. In a large study of African-American men and women (n = 14,419), we genotyped and analyzed 966,578 autosomal SNPs across the entire genome using a linear mixed model variance components approach implemented in the program GCTA (Yang et al Nat Genet 2010), and estimated an additive heritability of 44.7% (se: 3.7%) for this phenotype in a sample of evidently unrelated individuals. While this estimated value is similar to that given by Yang et al in their analyses, we remain concerned about two related issues: (1) whether in the complete absence of hidden relatedness, variance components methods have adequate power to estimate heritability when a very large number of SNPs are used in the analysis; and (2) whether estimation of heritability may be biased, in real studies, by low levels of residual hidden relatedness. We addressed the first question in a semi-analytic fashion by directly simulating the distribution of the score statistic for a test of zero heritability with and without low levels of relatedness. The second question was addressed by a very careful comparison of the behavior of estimated heritability for both observed (self-reported) height and simulated phenotypes compared to imputation R2 as a function of the number of SNPs used in the analysis. These simulations help to address the important question about whether today's GWAS SNPs will remain useful for imputing causal variants that are discovered using very large sample sizes in future studies of height, or whether the causal variants themselves will need to be genotyped de novo in order to build a prediction model that ultimately captures a large fraction of the variability of height, and by implication other complex phenotypes. Our overall conclusions are that when study sizes are quite large (5,000 or so) the additive heritability estimate for height is not apparently biased upwards using the linear mixed model; however there is evidence in our simulation that a very large number of causal variants (many thousands) each with very small effect on phenotypic variance will need to be discovered to fill the gap between the heritability explained by known versus unknown causal variants. We conclude that today's GWAS data will remain useful in the future for causal variant prediction, but that finding the causal variants that need to be predicted may be extremely laborious.
doi:10.1371/journal.pone.0131106
PMCID: PMC4488332  PMID: 26125186
16.  Prospective Investigation of Body Mass Index, Colorectal Adenoma, and Colorectal Cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial 
Journal of Clinical Oncology  2013;31(19):2450-2459.
Purpose
Obesity has consistently been linked to an increased risk of colorectal cancer, particularly among men. Whether body mass index (BMI) differentially influences the risk across the stages of colorectal cancer development remains unclear. We evaluated the associations of BMI with colorectal adenoma incidence, adenoma recurrence, and cancer in the context of a large screening trial, in which cases and controls had an equal chance for disease detection.
Methods
We prospectively evaluated the association between baseline BMI and the risk of incident distal adenoma (1,213 cases), recurrent adenoma (752 cases), and incident colorectal cancer (966 cases) among men and women, ages 55 to 74 years, randomly assigned to receive flexible sigmoidoscopy screening as part of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. We calculated odds ratios (ORs) and 95% CIs for adenoma incidence and recurrence, and hazard ratios (HRs) and 95% CIs for colorectal cancer incidence, using multivariable-adjusted models.
Results
Compared with normal-weight men (18.5 to 24.9 kg/m2), obese men (≥ 30 kg/m2) had significantly higher risk of incident adenoma (OR, 1.32; 95% CI, 1.06 to 1.65) and colorectal cancer (HR, 1.48; 95% CI, 1.16 to 1.89) and a borderline increased risk of recurrent adenoma (OR, 1.50; 95% CI, 0.98 to 2.30). No associations were observed for either adenoma or cancer in women.
Conclusion
Data from this large prospective study suggest that obesity is important throughout the natural history of colorectal cancer, at least in men, and colorectal cancer prevention efforts should encourage the achievement and maintenance of a healthy body weight in addition to regular screenings.
doi:10.1200/JCO.2012.48.4691
PMCID: PMC3691360  PMID: 23715565
17.  Dietary iron, iron homeostatic gene polymorphisms and the risk of advanced colorectal adenoma and cancer 
Carcinogenesis  2014;35(6):1276-1283.
Summary
Dietary iron intake and variation in iron homeostasis genes may affect colorectal neoplasia risk. This study examines the interaction of dietary iron intake and genetic variation in iron homeostatic genes on the outcomes of colorectal adenoma and colorectal cancer.
Dietary iron intake and variation in iron homeostasis genes may affect colorectal neoplasia risk. We conducted two nested case–control studies within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial: one of advanced colorectal adenoma (1205 cases; 1387 controls) and one of colorectal cancer (370 cases; 401 controls). Iron intake was estimated with a food frequency questionnaire and genotyping was performed for 21 genes. Unconditional logistic regression was used to estimate odds ratio (OR) and 95% confidence intervals (95% CIs) for colorectal neoplasia risk within quartiles of intake. Several single nucleotide polymorphisms (SNPs) modified the association between iron intake and the risk of adenoma or cancer. Dietary iron was positively associated with colorectal adenoma among three SNPs of HEPHL1, including carriers of the AA genotype at rs7946162 (ORQ4– Q1 = 2.22, 95% CI 1.15–4.27, P trend = 0.03; P interaction = 0.10), the TT genotype at rs2460063 (ORQ4– Q1 = 2.39, 95% CI 1.26–4.54, P trend = 0.02; P interaction = 0.04) and the GG genotype at rs7127348 (ORQ4– Q1 = 2.40, 95% CI 1.23–4.67, P trend = 0.02; P interaction = 0.09). Heme iron was positively associated with colorectal cancer among those with GG genotypes for ACO1 rs10970985 (ORQ4– Q 1 = 2.45, 95% CI 3.40–8.06, P trend = 0.004; P interaction = 0.05). However, none of the associations were statistically significant after adjustment for multiple comparisons. Future studies should target the specific genes and SNPs for which the association was significant prior to multiple comparison correction.
doi:10.1093/carcin/bgu028
PMCID: PMC4043236  PMID: 24536049
18.  Comparison of methods for fecal microbiome biospecimen collection 
BMC Microbiology  2014;14:103.
Background
Effective means are needed to efficiently collect fecal samples for microbiome analysis in large-scale epidemiological studies. Using twenty-four fecal aliquots prepared from three healthy individuals, we compared the following four fecal sample collection methods for assessment of human gut microbiome: 1) fecal occult blood test cards, held at room temperature for three days, 2) Eppendorf tubes, at room temperature for three days, 3) Eppendorf tubes with RNAlater, at room temperature, and 4) as controls, samples immediately frozen at −80°C. The 24 samples were assayed by 16S rRNA gene sequencing to compare overall microbiome structure and taxon distributions according to collection method.
Results
Storing fecal occult blood test card samples at room temperature for three days did not affect total DNA purity and relative 16S rRNA bacterial gene contents, compared with fresh frozen collection. Overall microbiome structure, based on phylogenetic UniFrac index, differed significantly by subject (p = 0.001), but microbiome structure (p = 0.497) and relative abundance of major microbial taxa (phyla) (p > 0.05) did not differ significantly by collection method.
Conclusions
Our findings suggest that low-cost fecal occult blood test card collection may be a feasible means of sample collection for fecal microbiome assessment in large-scale population-based studies.
doi:10.1186/1471-2180-14-103
PMCID: PMC4005852  PMID: 24758293
Comparison; Methods; Fecal; Microbiome; Collection
19.  Pleiotropic effects of genetic risk variants for other cancers on colorectal cancer risk: PAGE, GECCO, and CCFR Consortia 
Gut  2013;63(5):800-807.
Objective
Genome-wide association studies (GWAS) have identified a large number of single nucleotide polymorphisms (SNPs) associated with a wide array of cancer sites. Several of these variants demonstrate associations with multiple cancers, suggesting pleiotropic effects and shared biological mechanisms across some cancers. We hypothesized that SNPs previously associated with other cancers may additionally be associated with colorectal cancer. In a large-scale study, we examined 171 SNPs previously associated with 18 different cancers for their associations with colorectal cancer.
Design
We examined 13,338 colorectal cancer cases and 40,967 controls from three consortia: Population Architecture using Genetics and Epidemiology (PAGE), Genetic Epidemiology of Colorectal Cancer (GECCO), and the Colon Cancer Family Registry (CCFR). Study-specific logistic regression results, adjusted for age, sex, principal components of genetic ancestry, and/or study specific factors (as relevant) were combined using fixed-effect meta-analyses to evaluate the association between each SNP and colorectal cancer risk. A Bonferroni-corrected p-value of 2.92×10−4 was used to determine statistical significance of the associations.
Results
Two correlated SNPs— rs10090154 and rs4242382—in Region 1 of chromosome 8q24, a prostate cancer susceptibility region, demonstrated statistically significant associations with colorectal cancer risk. The most significant association was observed with rs4242382 (meta-analysis OR=1.12; 95% CI: 1.07–1.18; P=1.74×10−5), which also demonstrated similar associations across racial/ethnic populations and anatomical sub-sites.
Conclusion
This is the first study to clearly demonstrate Region 1 of chromosome 8q24 as a susceptibility locus for colorectal cancer, thus adding colorectal cancer to the list of cancer sites linked to this particular multi-cancer risk region at 8q24.
doi:10.1136/gutjnl-2013-305189
PMCID: PMC3918490  PMID: 23935004
colorectal cancer; pleiotropy; genome-wide association study; single nucleotide polymorphism
20.  Sex, Body Mass Index, and Dietary Fiber Intake Influence the Human Gut Microbiome 
PLoS ONE  2015;10(4):e0124599.
Increasing evidence suggests that the composition of the human gut microbiome is important in the etiology of human diseases; however, the personal factors that influence the gut microbiome composition are poorly characterized. Animal models point to sex hormone-related differentials in microbiome composition. In this study, we investigated the relationship of sex, body mass index (BMI) and dietary fiber intake with the gut microbiome in 82 humans. We sequenced fecal 16S rRNA genes by 454 FLX technology, then clustered and classified the reads to microbial genomes using the QIIME pipeline. Relationships of sex, BMI, and fiber intake with overall gut microbiome composition and specific taxon abundances were assessed by permutational MANOVA and multivariate logistic regression, respectively. We found that sex was associated with the gut microbiome composition overall (p=0.001). The gut microbiome in women was characterized by a lower abundance of Bacteroidetes (p=0.03). BMI (>25 kg/m2 vs. <25 kg/m2) was associated with the gut microbiome composition overall (p=0.05), and this relationship was strong in women (p=0.03) but not in men (p=0.29). Fiber from beans and from fruits and vegetables were associated, respectively, with greater abundance of Actinobacteria (p=0.006 and false discovery rate adjusted q=0.05) and Clostridia (p=0.009 and false discovery rate adjusted q=0.09). Our findings suggest that sex, BMI, and dietary fiber contribute to shaping the gut microbiome in humans. Better understanding of these relationships may have significant implications for gastrointestinal health and disease prevention.
doi:10.1371/journal.pone.0124599
PMCID: PMC4398427  PMID: 25874569
21.  Germline variation in NCF4, an innate immunity gene, is associated with an increased risk of colorectal cancer 
Chronic inflammation has been implicated in the etiology of colorectal adenoma and cancer; however, few key inflammatory genes mediating this relationship have been identified. In this study, we investigated the association of germline variation in innate immunity genes in relation to the risk of colorectal neoplasia. Our study was based on the analysis of samples collected from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. We investigated the association between 196 tag single nucleotide polymorphisms (SNPs) in 20 key innate immunity genes with risk of advanced colorectal adenoma and cancer in 719 adenoma cases, 481 cancer cases and 719 controls. Logistic regression was used to estimate odds ratios and 95% confidence intervals. After Bonferroni correction, the AG/GG genotype of rs5995355, which is upstream of NCF4, was associated with an increased risk of colorectal cancer (odds ratio [OR] 2.43, 95% confidence interval [95% CI] 1.73 – 3.39; P<0.0001). NCF4 is part of the NAPDH complex, a key factor in biochemical pathways and the innate immune response. While not definitive, our analyses suggest that the variant allele does not affect expression of NCF4, but rather modulates activity of the NADPH complex. Additional studies on the functional consequences of rs5995355 in NCF4 may help to clarify the mechanistic link between inflammation and colorectal cancer.
doi:10.1002/ijc.28457
PMCID: PMC3947351  PMID: 23982929
colorectal cancer; single nucleotide polymorphism; innate immunity; NCF4
22.  Do Environmental Factors Modify the Genetic Risk of Prostate Cancer? 
Background
Many SNPs influence prostate cancer risk. To what extent genetic risk can be reduced by environmental factors is unknown.
Methods
We evaluated effect modification by environmental factors of the association between susceptibility SNPs and prostate cancer in 1,230 incident prostate cancer cases and 1,361 controls, all white and similar ages, nested in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Trial. Genetic risk scores were calculated as number of risk alleles for 20 validated SNPs. We estimated the association between higher genetic risk (≥ 12 SNPs) and prostate cancer within environmental factor strata and tested for interaction.
Results
Men with ≥12 risk alleles had 1.98, 2.04, and 1.91 times the odds of total, advanced, and nonadvanced prostate cancer, respectively. These associations were attenuated with the use of selenium supplements, aspirin, ibuprofen, and higher vegetable intake. For selenium, the attenuation was most striking for advanced prostate cancer: compared with <12 alleles and no selenium, the OR for ≥12 alleles was 2.06 [95% confidence interval (CI), 1.67–2.55] in nonusers and 0.99 (0.38–2.58) in users (Pinteraction = 0.031). Aspirin had the most marked attenuation for nonadvanced prostate cancer: compared with <12 alleles and nonusers, the OR for ≥12 alleles was 2.25 (1.69–3.00) in nonusers and 1.70 (1.25–2.32) in users (Pinteraction = 0.009). This pattern was similar for ibuprofen (Pinteraction = 0.023) and vegetables (Pinteraction = 0.010).
Conclusions
This study suggests that selenium supplements may reduce genetic risk of advanced prostate cancer, whereas aspirin, ibuprofen, and vegetables may reduce genetic risk of nonadvanced prostate cancer.
doi:10.1158/1055-9965.EPI-14-0786-T
PMCID: PMC4337874  PMID: 25342390
23.  Oral microbiome and oral and gastrointestinal cancer risk 
Cancer causes & control : CCC  2012;23(3):399-404.
A growing body of evidence implicates human oral bacteria in the etiology of oral and gastrointestinal cancers. Epidemiological studies consistently report increased risks of these cancers in men and women with periodontal disease or tooth loss, conditions caused by oral bacteria. More than 700 bacterial species inhabit the oral cavity, including at least 11 bacterial phyla and 70 genera. Oral bacteria may activate alcohol and smoking-related carcinogens locally or act systemically, through chronic inflammation. High-throughput genetic-based assays now make it possible to comprehensively survey the human oral microbiome, the totality of bacteria in the oral cavity. Establishing the association of the oral microbiome with cancer risk may lead to significant advances in understanding of cancer etiology, potentially opening a new research paradigm for cancer prevention.
doi:10.1007/s10552-011-9892-7
PMCID: PMC3767140  PMID: 22271008
Human microbiome; Oral and gastrointestinal cancer; Assay; Epidemiology
24.  Human Gut Microbiome and Risk for Colorectal Cancer 
We tested the hypothesis that an altered community of gut microbes is associated with risk of colorectal cancer (CRC) in a study of 47 CRC case subjects and 94 control subjects. 16S rRNA genes in fecal bacterial DNA were amplified by universal primers, sequenced by 454 FLX technology, and aligned for taxonomic classification to microbial genomes using the QIIME pipeline. Taxonomic differences were confirmed with quantitative polymerase chain reaction and adjusted for false discovery rate. All statistical tests were two-sided. From 794217 16S rRNA gene sequences, we found that CRC case subjects had decreased overall microbial community diversity (P = .02). In taxonomy-based analyses, lower relative abundance of Clostridia (68.6% vs 77.8%) and increased carriage of Fusobacterium (multivariable odds ratio [OR] = 4.11; 95% confidence interval [CI] = 1.62 to 10.47) and Porphyromonas (OR = 5.17; 95% CI = 1.75 to 15.25) were found in case subjects compared with control subjects. Because of the potentially modifiable nature of the gut bacteria, our findings may have implications for CRC prevention.
doi:10.1093/jnci/djt300
PMCID: PMC3866154  PMID: 24316595
25.  Innate immunity gene polymorphisms and the risk of colorectal neoplasia 
Carcinogenesis  2013;34(11):2512-2520.
Inherited variation in genes that regulate innate immunity and inflammation may contribute to colorectal neoplasia risk. To evaluate this association, we conducted a nested case–control study of 451 colorectal cancer cases, 694 colorectal advanced adenoma cases and 696 controls of European descent within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. A total of 935 tag single-nucleotide polymorphisms (SNPs) in 98 genes were evaluated. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association with colorectal neoplasia. Sixteen SNPs were associated with colorectal neoplasia risk at P < 0.01, but after adjustment for multiple testing, only rs2838732 (ITGB2) remained suggestively associated with colorectal neoplasia (ORper T allele = 0.68, 95% CI: 0.57–0.83, P = 7.7 × 10–5, adjusted P = 0.07). ITGB2 codes for the CD18 protein in the integrin beta chain family. The ITGB2 association was stronger for colorectal cancer (ORper T allele = 0.41, 95% CI: 0.30–0.55, P = 2.4 × 10− 9) than for adenoma (ORper T allele = 0.84, 95%CI: 0.69–1.03, P = 0.08), but it did not replicate in the validation study. The ITGB2 rs2838732 association was significantly modified by smoking status (P value for interaction = 0.003). Among never and former smokers, it was inversely associated with colorectal neoplasia (ORper T allele = 0.5, 95% CI: 0.37–0.69 and ORper T allele = 0.72, 95% CI: 0.54–0.95, respectively), but no association was seen among current smokers. Other notable findings were observed for SNPs in BPI/LBP and MYD88. Although the results need to be replicated, our findings suggest that genetic variation in inflammation-related genes may be related to the risk of colorectal neoplasia.
doi:10.1093/carcin/bgt228
PMCID: PMC3810838  PMID: 23803696

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