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1.  The 6q22.33 Locus and Breast Cancer Susceptibility 
Recently, we identified a novel breast cancer (BC) susceptibility locus at 6q22.33 following a genome-wide association study (GWAS) in the Ashkenazi Jewish (AJ) genetic isolate. To replicate these findings, we performed case-control association analysis on 6q22.33 (rs2180341) in additional 487 AJ BC cases and in an independent non-Jewish (non-AJ), predominantly European-American (EU-Am), populations of 1,466 BC cases and 1,467 controls. We have confirmed the 6q22.33 association with BC risk in the replication cohorts (per-allele OR=1.18, 95%CI 1.04–1.33, p=0.0083) with the strongest effect in the aggregate meta-analysis of 3,039 BC cases and 2,616 AJ and non-AJ controls (per-allele OR=1.24, 95%CI 1.13–1.36, P=3.85×10−7).
We have also shown that the association was slightly stronger with ER positive tumors (per-allele OR=1.35, 95%CI 1.20–1.51, p=2.2×10−5) compared to ER negative tumors (per-allele OR=1.19, 95%CI 0.97–1.47, p=0.1). Furthermore, this study provides a novel insight into the functional significance of 6q22.33 in BC susceptibility. Due to stronger association of 6q22.33 with ER-positive BC we examined the effect of candidate genes on ER response elements (ERE). Upon transfection of overexpressed RNF146 in the MCF-7 BC cell line, we observed diminished expression of an ERE reporter construct. This study confirms the association of 6q22.33 with BC, with slightly stronger effect in ER positive tumors. Further functional studies of candidate genes are in progress and a large replication analysis is being completed as part of an international consortium.
PMCID: PMC4286363  PMID: 19690183
Ashkenazi Jews; Breast Cancer; Genome-wide association studies; SNPs; estrogen receptor
2.  The Association between Executive Function and Mortality in Homebound Elders 
To determine the association between executive function and mortality in homebound elders.
Longitudinal study
Four homecare agencies in the Boston area.
One thousand one hundred and seventy-two homebound elders aged 60 and older and with 8 year follow-up for mortality.
Different cognitive domains including executive, memory, and language functions were evaluated at baseline. Executive function was measured by the Trail-making Test B (Trails B), and the subjects were divided into 4 subgroups from the lowest to highest Trails B scores. The second cross-group analyses were used to compare those who were alive and those were deceased. Multivariate logistic regressions were used to determine whether there was an association between the level of Trails B scores and mortality.
At baseline, 436 (37.2%) homebound elders had the maximum Trails B scores (≥ 300), which indicated slowest performance. At the 8-year follow up, we found that 381 (32.5%) participants had died. The elderly with the highest Trails B scores were more than twice as likely to die when compared to those with the lowest scores (0–99) (OR = 2.39, 95% CI, 1.27–4.52, p = .003) after adjusting for the confounders including medical comorbidities related to death. In contrast, the other cognitive domains including memory and language were not associated with mortality in the same model.
Many homebound elderly have multiple medical conditions, and executive function may be crucial for the elderly to take care of their medical conditions and affect the outcome of death.
PMCID: PMC3919053  PMID: 24479144
homebound elders; executive function; mortality
3.  The Distribution of High-Risk Human Papillomaviruses Is Different in Young and Old Patients with Cervical Cancer 
PLoS ONE  2014;9(10):e109406.
Despite numerous human papillomavirus (HPV) frequency studies in women with cervical cancer (CC), little is known of HPV frequency trends according to patient age. In this work, we compare the mean age and frequency distribution by age of CC patients positive for different HPVs. This study included 462 CC patients. HPVs were detected by PCR and typed using DNA sequencing. A total of 456 patients (98.7%) were positive for HPV: 418 (90.5%) had single and 38 (8.2%) had double HPV infections. HPV16 (46.5%), HPV18 (10.4%), HPV45 (6.7%), and HPV31 (4.1%) were the most frequent viral types in single-infected patients. The mean ages of single-infected patients with HPV16 (49.2±13.3), HPV18 (47.9±12.2), HPV45 (47.9±11.7), or HPV39 (42.6±8.9) were significantly lower than the mean ages of patients singly (53.9±12.7; p<0.001, t-test) or doubly (55.4±12.7; p<0.05, t-test) infected with the remaining HPVs. Three different trends were identified: one for HPV16, another for HPVs18/45/39, and a third for the rest of HPVs. The frequency trend of HPV16 shows two peaks. The first (63.2%) was found in the youngest women (≤35 years), followed by a decreasing trend until the age of 55–60 years (31.1%). The second peak arose at 61–65 years (52.5%), followed by a decreasing trend. The trend for HPVs18/45/39 declined from the youngest (19.3%) to the oldest (>70 years; 12.8%) women. In contrast, the trend for the remaining HPVs increased from the youngest (15.8%) to the oldest (46.2%) women. Unlike other life-style factors, low-risk sexual behavior was associated with late onset of CC independent of low-oncogenic HPV types (p<0.05, Wald chi-square statistic). The data indicate that most CCs in young women depend on the presence of high-oncogenic HPVs. In contrast, almost half of CCs in older patients had low-oncogenic HPVs, suggesting they could depend on the presence of other factors.
PMCID: PMC4190176  PMID: 25295590
4.  Arginine 383 is a crucial residue in ABCG2 biogenesis 
Biochimica et biophysica acta  2009;1788(7):1434-1443.
ABCG2 is an ATP-binding cassette half-transporter initially identified in multidrug-resistant cancer cell lines and recently suggested to play an important role in pharmacokinetics. Here we report studies of a conserved arginine predicted to localize near the cytoplasmic side of TM1. First, we determined the effect of losing charge and bulk at this position via substitutions with glycine and alanine. The R383G mutant when transfected into HEK cells was not detectable on immunoblot or by functional assay, while the R383A mutant exhibited detectable but significantly decreased levels compared to wild-type, partial retention in the ER and altered glycosylation. Efflux of the ABCG2-substrates mitoxantrone and pheophorbide a was observed. Our experiments suggested rapid degradation of the R383A mutant by the proteasome via a kifunensine-insensitive pathway. Interestingly, overnight treatment of the R383A mutant with mitoxantrone assisted in protein maturation as evidenced by a shift to the N-glycosylated form. The R383A mutant when expressed in insect cells, though detected on the surface, had no measurable ATPase activity. In addition, substitution with the positively charged lysine resulted in significantly decreased protein expression levels in HEK cells, while retaining function. In conclusion, arginine 383 is a crucial residue for ABCG2 biogenesis, where even the most conservative mutations have a large impact.
PMCID: PMC4163909  PMID: 19406100
ABCG2; ABC transporter; membrane protein; mutagenesis; biogenesis
5.  Somatic alterations contributing to metastasis of a castration resistant prostate cancer 
Human mutation  2013;34(9):1231-1241.
Metastatic castration resistant prostate cancer (mCRPC) is a lethal disease and molecular markers that differentiate indolent from aggressive subtypes are needed. We sequenced the exomes of five metastatic tumors and healthy kidney tissue from an index case with mCRPC to identify lesions associated with disease progression and metastasis. An Ashkenazi Jewish (AJ) germline founder mutation, del185AG in BRCA1, was observed and AJ ancestry was confirmed. Sixty-two somatic variants altered proteins in tumors, including cancer-associated genes, TMPRSS2-ERG, PBRM1, and TET2. The majority (n=53) of somatic variants were present in all metastases and only a subset (n=31) was observed in the primary tumor. Integrating tumor next generation sequencing (NGS) and DNA copy number showed somatic loss of BRCA1 and TMPRSS2-ERG. We sequenced 19 genes with deleterious mutations in the index case in additional mCRPC samples and detected a frameshift, two somatic missense alterations, tumor loss of heterozygosity (LOH), and combinations of germline missense SNPs in TET2. In summary, genetic analysis of metastases from an index case permitted us to infer a chronology for the clonal spread of disease based on sequential accrual of somatic lesions. The role of TET2 in mCRPC deserves additional analysis and may define a subset of metastatic disease.
PMCID: PMC3745530  PMID: 23636849
tumor heterogeneity; somatic mutation; metastasis; epigenetic modifiers; BRCA1; TMPRSS2; ERG; PBRM1; TET2
6.  Inherited GATA3 variants are associated with Ph-like childhood acute lymphoblastic leukemia and risk of relapse 
Nature genetics  2013;45(12):1494-1498.
Recent genomic profiling of childhood acute lymphoblastic leukemia (ALL) identified a novel high-risk subtype with a gene expression signature resembling Philadelphia chromosome-positive ALL and a poor prognosis (Ph-like ALL). However, the role of inherited genetic variation in Ph-like ALL pathogenesis remains unknown. In a genome-wide association study (GWAS) of 511 ALL cases and 6,661 non-ALL controls, we identified a single susceptibility locus for Ph-like ALL (GATA3, rs3824662, P=2.17×10−14, odds ratio [OR]=3.85, for Ph-like ALL vs. non-ALL; P=1.05×10−8, OR=3.25, for Ph-like ALL vs. non-Ph-like ALL) that was independently validated. The rs3824662 risk allele was associated with somatic lesions underlying Ph-like ALL (i.e., CRLF2 rearrangement, JAK mutation, and IKZF1 deletion) and directly influenced GATA3 transcription. Finally, GATA3 SNP genotype was also associated with early treatment response and the risk of ALL relapse. Our results provide insights into interactions between host and tumor genomes and their importance in ALL pathogenesis and prognosis.
PMCID: PMC4039076  PMID: 24141364
7.  Novel Susceptibility Variants at 10p12.31-12.2 for Childhood Acute Lymphoblastic Leukemia in Ethnically Diverse Populations 
Acute lymphoblastic leukemia (ALL) is the most common cancer in children and the incidence of ALL varies by ethnicity. Although accumulating evidence indicates inherited predisposition to ALL, the genetic basis of ALL susceptibility in diverse ancestry has not been comprehensively examined.
We performed a multiethnic genome-wide association study in 1605 children with ALL and 6661 control subjects after adjusting for population structure, with validation in three replication series of 845 case subjects and 4316 control subjects. Association was tested by two-sided logistic regression.
A novel ALL susceptibility locus at 10p12.31-12.2 (BMI1-PIP4K2A, rs7088318, P = 1.1×10−11) was identified in the genome-wide association study, with independent replication in European Americans, African Americans, and Hispanic Americans (P = .001, .009, and .04, respectively). Association was also validated at four known ALL susceptibility loci: ARID5B, IKZF1, CEBPE, and CDKN2A/2B. Associations at ARID5B, IKZF1, and BMI1-PIP4K2A variants were consistent across ethnicity, with multiple independent signals at IKZF1 and BMI1-PIP4K2A loci. The frequency of ARID5B and BMI1-PIP4K2A variants differed by ethnicity, in parallel with ethnic differences in ALL incidence. Suggestive evidence for modifying effects of age on genetic predisposition to ALL was also observed. ARID5B, IKZF1, CEBPE, and BMI1-PIP4K2A variants cumulatively conferred strong predisposition to ALL, with children carrying six to eight copies of risk alleles at a ninefold (95% confidence interval = 6.9 to 11.8) higher ALL risk relative to those carrying zero to one risk allele at these four single nucleotide polymorphisms.
These findings indicate strong associations between inherited genetic variation and ALL susceptibility in children and shed new light on ALL molecular etiology in diverse ancestry.
PMCID: PMC3691938  PMID: 23512250
8.  Promoter variants in the MSMB gene associated with prostate cancer regulate MSMB/NCOA4 fusion transcripts 
Human genetics  2012;131(9):1453-1466.
Beta-microseminoprotein (MSP)/MSMB is an immunoglobulin superfamily protein synthesized by prostate epithelial cells and secreted into seminal plasma. Variants in the promoter of the MSMB gene have been associated with the risk of prostate cancer (PCa) in several independent genome-wide association studies. Both MSMB and an adjacent gene, NCOA4, are subjected to transcriptional control via androgen response elements. The gene product of NCOA4 interacts directly with the androgen receptor as a co-activator to enhance AR transcriptional activity. Here, we provide evidence for the expression of full-length MSMB-NCOA4 fusion transcripts regulated by the MSMB promoter. The predominant MSMB-NCOA4 transcript arises by fusion of the 5′UTR and exons 1–2 of the MSMB pre-mRNA, with exons 2–10 of the NCOA4 premRNA, producing a stable fusion protein, comprising the essential domains of NCOA4. Analysis of the splice sites of this transcript shows an unusually strong splice acceptor at NCOA4 exon 2 and the presence of Alu repeats flanking the exons potentially involved in the splicing event. Transfection experiments using deletion clones of the promoter coupled with luciferase reporter assays define a core MSMB promoter element located between –27 and –236 of the gene, and a negative regulatory element immediately upstream of the start codon. Computational network analysis reveals that the MSMB gene is functionally connected to NCOA4 and the androgen receptor signaling pathway. The data provide an example of how GWAS-associated variants may have multiple genetic and epigenetic effects.
PMCID: PMC3956317  PMID: 22661295
9.  Structural Analogues of Smoothened Intracellular Loops as Potent Inhibitors of Hedgehog Pathway and Cancer Cell Growth 
Journal of medicinal chemistry  2007;50(18):4534-4538.
Smoothened is a critical component of the Hedgehog pathway that is essential for stem cell renewal and is dysregulated in many cancer types. We have found synthetic analogues of the second and third intracellular loops of smoothened to be potent inhibitors of the Hedgehog pathway. Palmitoylated peptides as short as 10 residues inhibited melanoma cells growth with IC50 in the low nanomolar range. The compounds are promising drug candidates and convenient tools for solving mechanisms of Hedgehog signaling.
PMCID: PMC3956439  PMID: 17685505
10.  Rationale, Timeline, Study Design, and Protocol Overview of the Therapeutic Hypothermia After Pediatric Cardiac Arrest Trials 
To describe the rationale, timeline, study design, and protocol overview of the Therapeutic Hypothermia after Pediatric Cardiac Arrest trials.
Multicenter randomized controlled trials.
Pediatric intensive care and cardiac ICUs in the United States and Canada.
Children from 48 hours to 18 years old, who have return of circulation after cardiac arrest, who meet trial eligibility criteria, and whose guardians provide written consent.
Therapeutic hypothermia or therapeutic normothermia.
Measurements and Main Results
From concept inception in 2002 until trial initiation in 2009, 7 years were required to plan and operationalize the Therapeutic Hypothermia after Pediatric Cardiac Arrest trials. Two National Institute of Child Health and Human Development clinical trial planning grants (R21 and R34) supported feasibility assessment and protocol development. Two clinical research networks, Pediatric Emergency Care Applied Research Network and Collaborative Pediatric Critical Care Research Network, provided infrastructure resources. Two National Heart Lung Blood Institute U01 awards provided funding to conduct separate trials of in-hospital and out-of-hospital cardiac arrest. A pilot vanguard phase that included half the clinical sites began on March 9, 2009, and this was followed by full trial funding through 2015.
Over a decade will have been required to plan, design, operationalize, and conduct the Therapeutic Hypothermia after Pediatric Cardiac Arrest trials. Details described in this report, such as participation of clinical research networks and clinical trial planning grants utilization, may be of utility for individuals who are planning investigator-initiated, federally supported clinical trials.
PMCID: PMC3947631  PMID: 23842585
cardiac arrest; in hospital; mortality; multicenter; outcome; out of hospital; pediatric; randomized controlled trial; targeted temperature control; therapeutic hypothermia; therapeutic normothermia
11.  Association between Amylin and Amyloid-β Peptides in Plasma in the Context of Apolipoprotein E4 Allele 
PLoS ONE  2014;9(2):e88063.
Amylin, a pancreatic peptide that readily crosses the blood brain barrier (BBB), and amyloid-beta peptide (Aβ), the main component of amyloid plaques and a major component of Alzheimer's disease (AD) pathology in the brain, share several features. These include having similar β-sheet secondary structures, binding to the same receptor, and being degraded by the same protease. Thus, amylin may be associated with Aβ, but the nature of their relationship remains unclear. In this study, we used human samples to study the relationship between plasma amylin and Aβ in the context of the apolipoprotein E alleles (ApoE). We found that concentrations of Aβ1-42 (P<0.0001) and Aβ1-40 (P<0.0001) increased with each quartile increase of amylin. Using multivariate regression analysis, the study sample showed that plasma amylin was associated with Aβ1-42 (β = +0.149, SE = 0.025, P<0.0001) and Aβ1-40 (β = +0.034, SE = 0.016, P = 0.04) as an outcome after adjusting for age, gender, ethnicity, ApoE4, BMI, diabetes, stroke, kidney function and lipid profile. This positive association between amylin and Aβ1-42 in plasma was found regardless of the ApoE genotype. In contrast, the relationship between amylin and Aβ1-40 in plasma seen in ApoE4 non-carriers disappeared in the presence of ApoE4. Using AD mouse models, our recent study demonstrates that intraperitoneal (i.p.) injection of synthetic amylin enhances the removal of Aβ from the brain into blood, thus resulting in increased blood levels of both amylin and Aβ. The positive association between amylin and Aβ, especially Aβ1-42, in human blood samples is probably relevant to the findings in the AD mouse models. The presence of ApoE4 may attenuate amylin's capacity to remove Aβ, especially Aβ1-40, from the AD brain.
PMCID: PMC3919737  PMID: 24520345
12.  Genetics and genomics of prostate cancer 
Asian Journal of Andrology  2013;15(3):309-313.
Prostate cancer (PCa) is one of the most common malignancies in the world with over 890 000 cases and over 258 000 deaths worldwide each year. Nearly all mortalities from PCa are due to metastatic disease, typically through tumors that evolve to be hormone-refractory or castrate-resistant. Despite intensive epidemiological study, there are few known environmental risk factors, and age and family history are the major determinants. However, there is extreme heterogeneity in PCa incidence worldwide, suggesting that major determining factors have not been described. Genome-wide association studies have been performed and a considerable number of significant, but low-risk loci have been identified. In addition, several groups have analyzed PCa by determination of genomic copy number, fusion gene generation and targeted resequencing of candidate genes, as well as exome and whole genome sequencing. These initial studies have examined both primary and metastatic tumors as well as murine xenografts and identified somatic alterations in TP53 and other potential driver genes, and the disturbance of androgen response and cell cycle pathways. It is hoped that continued characterization of risk factors as well as gene mutation and misregulation in tumors will aid in understanding, diagnosing and better treating PCa.
PMCID: PMC3739637  PMID: 23564043
androgen receptor; cancer progression; chromatin remodeling; metastasis; prostate cancer (PCa); risk factor; somatic mutation; tumor heterogeneity
13.  ARID5B Genetic Polymorphisms Contribute to Racial Disparities in the Incidence and Treatment Outcome of Childhood Acute Lymphoblastic Leukemia 
Journal of Clinical Oncology  2012;30(7):751-757.
Recent genome-wide screens have identified genetic variations in ARID5B associated with susceptibility to childhood acute lymphoblastic leukemia (ALL). We sought to determine the contribution of ARID5B single nucleotide polymorphisms (SNPs) to racial disparities in ALL susceptibility and treatment outcome.
Patients and Methods
We compared the association between ARID5B SNP genotype and ALL susceptibility in whites (> 95% European genetic ancestry; 978 cases and 1,046 controls) versus in Hispanics (> 10% Native American ancestry; 330 cases and 541 controls). We determined the relationships between ARID5B SNP genotype and ALL relapse risk in 1,605 children treated on the Children's Oncology Group (COG) P9904/9905 clinical trials.
Among 49 ARID5B SNPs interrogated, 10 were significantly associated with ALL susceptibility in both whites and Hispanics (P < .05), with risk alleles consistently more frequent in Hispanics than in whites. rs10821936 exhibited the most significant association in both races (P = 8.4 × 10−20 in whites; P = 1 × 10−6 in Hispanics), and genotype at this SNP was highly correlated with local Native American genetic ancestry (P = 1.8 × 10−8). Multivariate analyses in Hispanics identified an additional SNP associated with ALL susceptibility independent of rs10821936. Eight ARID5B SNPs were associated with both ALL susceptibility and relapse hazard; the alleles related to higher ALL incidence were always linked to poorer treatment outcome and were more frequent in Hispanics.
ARID5B polymorphisms are important determinants of childhood ALL susceptibility and treatment outcome, and they contribute to racial disparities in this disease.
PMCID: PMC3295551  PMID: 22291082
15.  Association Assessment of Copy Number Polymorphism and Risk of Age-Related Macular Degeneration 
Ophthalmology  2011;118(12):2442-2446.
We previously identified a genetic copy number polymorphism (CNP147) that was statistically associated with age-related macular degeneration (AMD), and which resides downstream of the complement factor H (CFH) gene. Factor H protein is polymorphic at amino acid 402 in which the resulting histidine containing moiety has been established to impart significant risk of AMD. Here we present a method to precisely determine the exact copy number of CNP147 and examine in more detail the association with AMD.
Case-control Study
421 AREDS (Age-related Eye Disease cohort Study) subjects of whom approximately 35% were diagnosed with neovascular disease, 19% with geographic atrophy, 16% with both, 30% with large drusen and 215 controls.
Using copy number assays available from Applied Biosystems Inc., we examined four loci spanning CNP147 and neighboring CNP148 in an AREDS matched case-control sample set. We analyzed these data by copy number while controlling for two high-risk CFH variants, rs1061170 (Y402H) and rs1410996. We phased the high risk CFH variants with CNP147 and analyzed haplotype frequencies in cases and controls. To further validate copy numbers, six Utah CEPH families (Centre D’etude du Polymorphism Humaine) were typed for CNP147 and the segregation assessed.
Main Outcome Measures
Increased or decreased risk of AMD from genetic loci.
Having fewer than 2 copies of CNP147 is associated with an estimated 43% reduction in odds of having AMD in this sample set (adjusted odds ratio=0.57, P=0.006). CNP148 variation is rare in Caucasians and it was not statistically significant. Common haplotypes reveal that the risk alleles for rs1061170 and rs1410996 most frequently segregate with higher copy numbers for CNP147; but not exclusively, and that one haplotype that carried a deletion of CNP147 was highly protective (odds ratio=0.25 P=1.3×10−13) when compared to the reference.
In this matched subset of AREDS subjects, after adjusting for two known risk variants in CFH, CNP147 deletion statistically associates with diminished risk for AMD.
PMCID: PMC3223559  PMID: 21856016
Copy number polymorphism; age-related macular degeneration; HapMap 3; TaqMan Copy Number Assays; qPCR
16.  Detectable clonal mosaicism and its relationship to aging and cancer 
Jacobs, Kevin B | Yeager, Meredith | Zhou, Weiyin | Wacholder, Sholom | Wang, Zhaoming | Rodriguez-Santiago, Benjamin | Hutchinson, Amy | Deng, Xiang | Liu, Chenwei | Horner, Marie-Josephe | Cullen, Michael | Epstein, Caroline G | Burdett, Laurie | Dean, Michael C | Chatterjee, Nilanjan | Sampson, Joshua | Chung, Charles C | Kovaks, Joseph | Gapstur, Susan M | Stevens, Victoria L | Teras, Lauren T | Gaudet, Mia M | Albanes, Demetrius | Weinstein, Stephanie J | Virtamo, Jarmo | Taylor, Philip R | Freedman, Neal D | Abnet, Christian C | Goldstein, Alisa M | Hu, Nan | Yu, Kai | Yuan, Jian-Min | Liao, Linda | Ding, Ti | Qiao, You-Lin | Gao, Yu-Tang | Koh, Woon-Puay | Xiang, Yong-Bing | Tang, Ze-Zhong | Fan, Jin-Hu | Aldrich, Melinda C | Amos, Christopher | Blot, William J | Bock, Cathryn H | Gillanders, Elizabeth M | Harris, Curtis C | Haiman, Christopher A | Henderson, Brian E | Kolonel, Laurence N | Le Marchand, Loic | McNeill, Lorna H | Rybicki, Benjamin A | Schwartz, Ann G | Signorello, Lisa B | Spitz, Margaret R | Wiencke, John K | Wrensch, Margaret | Wu, Xifeng | Zanetti, Krista A | Ziegler, Regina G | Figueroa, Jonine D | Garcia-Closas, Montserrat | Malats, Nuria | Marenne, Gaelle | Prokunina-Olsson, Ludmila | Baris, Dalsu | Schwenn, Molly | Johnson, Alison | Landi, Maria Teresa | Goldin, Lynn | Consonni, Dario | Bertazzi, Pier Alberto | Rotunno, Melissa | Rajaraman, Preetha | Andersson, Ulrika | Freeman, Laura E Beane | Berg, Christine D | Buring, Julie E | Butler, Mary A | Carreon, Tania | Feychting, Maria | Ahlbom, Anders | Gaziano, J Michael | Giles, Graham G | Hallmans, Goran | Hankinson, Susan E | Hartge, Patricia | Henriksson, Roger | Inskip, Peter D | Johansen, Christoffer | Landgren, Annelie | McKean-Cowdin, Roberta | Michaud, Dominique S | Melin, Beatrice S | Peters, Ulrike | Ruder, Avima M | Sesso, Howard D | Severi, Gianluca | Shu, Xiao-Ou | Visvanathan, Kala | White, Emily | Wolk, Alicja | Zeleniuch-Jacquotte, Anne | Zheng, Wei | Silverman, Debra T | Kogevinas, Manolis | Gonzalez, Juan R | Villa, Olaya | Li, Donghui | Duell, Eric J | Risch, Harvey A | Olson, Sara H | Kooperberg, Charles | Wolpin, Brian M | Jiao, Li | Hassan, Manal | Wheeler, William | Arslan, Alan A | Bas Bueno-de-Mesquita, H | Fuchs, Charles S | Gallinger, Steven | Gross, Myron D | Holly, Elizabeth A | Klein, Alison P | LaCroix, Andrea | Mandelson, Margaret T | Petersen, Gloria | Boutron-Ruault, Marie-Christine | Bracci, Paige M | Canzian, Federico | Chang, Kenneth | Cotterchio, Michelle | Giovannucci, Edward L | Goggins, Michael | Bolton, Judith A Hoffman | Jenab, Mazda | Khaw, Kay-Tee | Krogh, Vittorio | Kurtz, Robert C | McWilliams, Robert R | Mendelsohn, Julie B | Rabe, Kari G | Riboli, Elio | Tjønneland, Anne | Tobias, Geoffrey S | Trichopoulos, Dimitrios | Elena, Joanne W | Yu, Herbert | Amundadottir, Laufey | Stolzenberg-Solomon, Rachael Z | Kraft, Peter | Schumacher, Fredrick | Stram, Daniel | Savage, Sharon A | Mirabello, Lisa | Andrulis, Irene L | Wunder, Jay S | García, Ana Patiño | Sierrasesúmaga, Luis | Barkauskas, Donald A | Gorlick, Richard G | Purdue, Mark | Chow, Wong-Ho | Moore, Lee E | Schwartz, Kendra L | Davis, Faith G | Hsing, Ann W | Berndt, Sonja I | Black, Amanda | Wentzensen, Nicolas | Brinton, Louise A | Lissowska, Jolanta | Peplonska, Beata | McGlynn, Katherine A | Cook, Michael B | Graubard, Barry I | Kratz, Christian P | Greene, Mark H | Erickson, Ralph L | Hunter, David J | Thomas, Gilles | Hoover, Robert N | Real, Francisco X | Fraumeni, Joseph F | Caporaso, Neil E | Tucker, Margaret | Rothman, Nathaniel | Pérez-Jurado, Luis A | Chanock, Stephen J
Nature genetics  2012;44(6):651-658.
In an analysis of 31,717 cancer cases and 26,136 cancer-free controls drawn from 13 genome-wide association studies (GWAS), we observed large chromosomal abnormalities in a subset of clones from DNA obtained from blood or buccal samples. Mosaic chromosomal abnormalities, either aneuploidy or copy-neutral loss of heterozygosity, of size >2 Mb were observed in autosomes of 517 individuals (0.89%) with abnormal cell proportions between 7% and 95%. In cancer-free individuals, the frequency increased with age; 0.23% under 50 and 1.91% between 75 and 79 (p=4.8×10−8). Mosaic abnormalities were more frequent in individuals with solid-tumors (0.97% versus 0.74% in cancer-free individuals, OR=1.25, p=0.016), with a stronger association for cases who had DNA collected prior to diagnosis or treatment (OR=1.45, p=0.0005). Detectable clonal mosaicism was common in individuals for whom DNA was collected at least one year prior to diagnosis of leukemia compared to cancer-free individuals (OR=35.4, p=3.8×10−11). These findings underscore the importance of the role and time-dependent nature of somatic events in the etiology of cancer and other late-onset diseases.
PMCID: PMC3372921  PMID: 22561519
17.  Evidence of association of APOE with age-related macular degeneration - a pooled analysis of 15 studies 
Human mutation  2011;32(12):1407-1416.
Age-related macular degeneration (AMD) is the most common cause of incurable visual impairment in high-income countries. Previous studies report inconsistent associations between AMD and apolipoprotein E (APOE), a lipid transport protein involved in low-density cholesterol modulation. Potential interaction between APOE and sex, and smoking status, has been reported. We present a pooled analysis (n=21,160) demonstrating associations between late AMD and APOε4 (OR=0.72 per haplotype; CI: 0.65–0.74; P=4.41×10−11) and APOε2 (OR=1.83 for homozygote carriers; CI: 1.04–3.23; P=0.04), following adjustment for age-group and sex within each study and smoking status. No evidence of interaction between APOE and sex or smoking was found. Ever smokers had significant increased risk relative to never smokers for both neovascular (OR=1.54; CI: 1.38–1.72; P=2.8×10−15) and atrophic (OR=1.38; CI: 1.18–1.61; P=3.37×10−5) AMD but not early AMD (OR=0.94; CI: 0.86–1.03; P=0.16), implicating smoking as a major contributing factor to disease progression from early signs to the visually disabling late forms. Extended haplotype analysis incorporating rs405509 did not identify additional risks beyondε2 and ε4 haplotypes. Our expanded analysis substantially improves our understanding of the association between the APOE locus and AMD. It further provides evidence supporting the role of cholesterol modulation, and low-density cholesterol specifically, in AMD disease etiology.
PMCID: PMC3217135  PMID: 21882290
age-related macular degeneration; AMD; apolipoprotein E; APOE; case-control association study
18.  Haplotype structure in Ashkenazi Jewish BRCA1 and BRCA2 mutation carriers 
Im, Kate M. | Kirchhoff, Tomas | Wang, Xianshu | Green, Todd | Chow, Clement Y. | Vijai, Joseph | Korn, Joshua | Gaudet, Mia M. | Fredericksen, Zachary | Pankratz, V. Shane | Guiducci, Candace | Crenshaw, Andrew | McGuffog, Lesley | Kartsonaki, Christiana | Morrison, Jonathan | Healey, Sue | Sinilnikova, Olga M. | Mai, Phuong L. | Greene, Mark H. | Piedmonte, Marion | Rubinstein, Wendy S. | Hogervorst, Frans B. | Rookus, Matti A. | Collée, J. Margriet | Hoogerbrugge, Nicoline | van Asperen, Christi J. | Meijers-Heijboer, Hanne E. J. | Van Roozendaal, Cees E. | Caldes, Trinidad | Perez-Segura, Pedro | Jakubowska, Anna | Lubinski, Jan | Huzarski, Tomasz | Blecharz, Paweł | Nevanlinna, Heli | Aittomäki, Kristiina | Lazaro, Conxi | Blanco, Ignacio | Barkardottir, Rosa B. | Montagna, Marco | D'Andrea, Emma | Devilee, Peter | Olopade, Olufunmilayo I. | Neuhausen, Susan L. | Peissel, Bernard | Bonanni, Bernardo | Peterlongo, Paolo | Singer, Christian F. | Rennert, Gad | Lejbkowicz, Flavio | Andrulis, Irene L. | Glendon, Gord | Ozcelik, Hilmi | Toland, Amanda Ewart | Caligo, Maria Adelaide | Beattie, Mary S. | Chan, Salina | Domchek, Susan M. | Nathanson, Katherine L. | Rebbeck, Timothy R. | Phelan, Catherine | Narod, Steven | John, Esther M. | Hopper, John L. | Buys, Saundra S. | Daly, Mary B. | Southey, Melissa C. | Terry, Mary-Beth | Tung, Nadine | Hansen, Thomas v. O. | Osorio, Ana | Benitez, Javier | Durán, Mercedes | Weitzel, Jeffrey N. | Garber, Judy | Hamann, Ute | Peock, Susan | Cook, Margaret | Oliver, Clare T. | Frost, Debra | Platte, Radka | Evans, D. Gareth | Eeles, Ros | Izatt, Louise | Paterson, Joan | Brewer, Carole | Hodgson, Shirley | Morrison, Patrick J. | Porteous, Mary | Walker, Lisa | Rogers, Mark T. | Side, Lucy E. | Godwin, Andrew K. | Schmutzler, Rita K. | Wappenschmidt, Barbara | Laitman, Yael | Meindl, Alfons | Deissler, Helmut | Varon-Mateeva, Raymonda | Preisler-Adams, Sabine | Kast, Karin | Venat-Bouvet, Laurence | Stoppa-Lyonnet, Dominique | Chenevix-Trench, Georgia | Easton, Douglas F. | Klein, Robert J. | Daly, Mark J. | Friedman, Eitan | Dean, Michael | Clark, Andrew G. | Altshuler, David M. | Antoniou, Antonis C. | Couch, Fergus J. | Offit, Kenneth | Gold, Bert
Human genetics  2011;130(5):685-699.
Abstract Three founder mutations in BRCA1 and BRCA2 contribute to the risk of hereditary breast and ovarian cancer in Ashkenazi Jews (AJ). They are observed at increased frequency in the AJ compared to other BRCA mutations in Caucasian non-Jews (CNJ). Several authors have proposed that elevated allele frequencies in the surrounding genomic regions reflect adaptive or balancing selection. Such proposals predict long-range linkage dis-equilibrium (LD) resulting from a selective sweep, although genetic drift in a founder population may also act to create long-distance LD. To date, few studies have used the tools of statistical genomics to examine the likelihood of long-range LD at a deleterious locus in a population that faced a genetic bottleneck. We studied the genotypes of hundreds of women from a large international consortium of BRCA1 and BRCA2 mutation carriers and found that AJ women exhibited long-range haplotypes compared to CNJ women. More than 50% of the AJ chromosomes with the BRCA1 185delAG mutation share an identical 2.1 Mb haplotype and nearly 16% of AJ chromosomes carrying the BRCA2 6174delT mutation share a 1.4 Mb haplotype. Simulations based on the best inference of Ashkenazi population demography indicate that long-range haplotypes are expected in the context of a genome-wide survey. Our results are consistent with the hypothesis that a local bottleneck effect from population size constriction events could by chance have resulted in the large haplotype blocks observed at high frequency in the BRCA1 and BRCA2 regions of Ashkenazi Jews.
PMCID: PMC3196382  PMID: 21597964
19.  Homeopathy for mental fatigue: lessons from a randomized, triple blind, placebo-controlled cross-over clinical trial 
Difficulty in controlling attention can lead to mental fatigue in the healthy population. We identified one trial reporting a benefit in patients’ attention using a homeopathic formula preparation. One component of the preparation was potassium phosphate, widely available off the shelf as Kali phos 6x for cognitive problems. The aim of this exploratory trial was to assess the effectiveness of Kali phos 6x for attention problems associated with mental fatigue.
We recruited student and staff volunteers (University of York) with self-reported mental fatigue, excluding any using homeopathy or prescribed stimulants, or with a diagnosis of chronic fatigue syndrome. In a triple blind, cross-over, placebo-controlled clinical trial, 86 volunteers were randomized to receive Kali phos 6x or identical placebo 10 minutes before taking a psychological test of attention (Stroop Colour-Word Test). One week later they were crossed over and took the other preparation before repeating the test.
We found no evidence of a treatment effect in a comparison of Kali phos 6x with placebo (Kali phos minus placebo = −1.1 (95% CI −3.0 to 0.9, P = 0.3) Stroop score units, Cohen effect size = −0.17) even when allowing for a weak period effect with accuracy scores in the second period being higher than those in the first (P = 0.05). We observed a ceiling effect in the Stroop test which undermined our ability to interpret this result.
Kali phos 6x was not found to be effective in reducing mental fatigue. A ceiling effect in our primary outcome measure meant that we could not rule out a type II error. Thorough piloting of an adequate outcome measure could have led to an unequivocal result.
Current Controlled Trials
PMCID: PMC3517425  PMID: 23025450
Crossover study design; Mental fatigue; Kali phos 6x; Stroop test
20.  A locally funded Puerto Rican parrot (Amazona vittata) genome sequencing project increases avian data and advances young researcher education 
GigaScience  2012;1:14.
Amazona vittata is a critically endangered Puerto Rican endemic bird, the only surviving native parrot species in the United States territory, and the first parrot in the large Neotropical genus Amazona, to be studied on a genomic scale.
In a unique community-based funded project, DNA from an A. vittata female was sequenced using a HiSeq Illumina platform, resulting in a total of ~42.5 billion nucleotide bases. This provided approximately 26.89x average coverage depth at the completion of this funding phase. Filtering followed by assembly resulted in 259,423 contigs (N50 = 6,983 bp, longest = 75,003 bp), which was further scaffolded into 148,255 fragments (N50 = 19,470, longest = 206,462 bp). This provided ~76% coverage of the genome based on an estimated size of 1.58 Gb. The assembled scaffolds allowed basic genomic annotation and comparative analyses with other available avian whole-genome sequences.
The current data represents the first genomic information from and work carried out with a unique source of funding. This analysis further provides a means for directed training of young researchers in genetic and bioinformatics analyses and will facilitate progress towards a full assembly and annotation of the Puerto Rican parrot genome. It also adds extensive genomic data to a new branch of the avian tree, making it useful for comparative analyses with other avian species. Ultimately, the knowledge acquired from these data will contribute to an improved understanding of the overall population health of this species and aid in ongoing and future conservation efforts.
PMCID: PMC3626513  PMID: 23587420
Amazona vittata; Puerto rican parrot; Genome sequence; Annotation; Assembly; Local funding; Education
21.  Differential Gene and MicroRNA Expression between Etoposide Resistant and Etoposide Sensitive MCF7 Breast Cancer Cell Lines 
PLoS ONE  2012;7(9):e45268.
In order to develop targeted strategies for combating drug resistance it is essential to understand it’s basic molecular mechanisms. In an exploratory study we have found several possible indicators of etoposide resistance operating in MCF7VP cells, including up-regulation of ABC transporter genes, modulation of miRNA, and alteration in copy numbers of genes.
PMCID: PMC3445463  PMID: 23028896
22.  Single-cell sequencing analysis characterizes common and cell-lineage-specific mutations in a muscle-invasive bladder cancer 
GigaScience  2012;1:12.
Cancers arise through an evolutionary process in which cell populations are subjected to selection; however, to date, the process of bladder cancer, which is one of the most common cancers in the world, remains unknown at a single-cell level.
We carried out single-cell exome sequencing of 66 individual tumor cells from a muscle-invasive bladder transitional cell carcinoma (TCC). Analyses of the somatic mutant allele frequency spectrum and clonal structure revealed that the tumor cells were derived from a single ancestral cell, but that subsequent evolution occurred, leading to two distinct tumor cell subpopulations. By analyzing recurrently mutant genes in an additional cohort of 99 TCC tumors, we identified genes that might play roles in the maintenance of the ancestral clone and in the muscle-invasive capability of subclones of this bladder cancer, respectively.
This work provides a new approach of investigating the genetic details of bladder tumoral changes at the single-cell level and a new method for assessing bladder cancer evolution at a cell-population level.
PMCID: PMC3626503  PMID: 23587365
Single-cell exome sequencing; Bladder cancer; Tumor evolution; Population genetics
23.  Variations in Apolipoprotein E Frequency With Age in a Pooled Analysis of a Large Group of Older People 
American Journal of Epidemiology  2011;173(12):1357-1364.
Variation in the apolipoprotein E gene (APOE) has been reported to be associated with longevity in humans. The authors assessed the allelic distribution of APOE isoforms ε2, ε3, and ε4 among 10,623 participants from 15 case-control and cohort studies of age-related macular degeneration (AMD) in populations of European ancestry (study dates ranged from 1990 to 2009). The authors included only the 10,623 control subjects from these studies who were classified as having no evidence of AMD, since variation within the APOE gene has previously been associated with AMD. In an analysis stratified by study center, gender, and smoking status, there was a decreasing frequency of the APOE ε4 isoform with increasing age (χ2 for trend = 14.9 (1 df); P = 0.0001), with a concomitant increase in the ε3 isoform (χ2 for trend = 11.3 (1 df); P = 0.001). The association with age was strongest in ε4 homozygotes; the frequency of ε4 homozygosity decreased from 2.7% for participants aged 60 years or less to 0.8% for those over age 85 years, while the proportion of participants with the ε3/ε4 genotype decreased from 26.8% to 17.5% across the same age range. Gender had no significant effect on the isoform frequencies. This study provides strong support for an association of the APOE gene with human longevity.
PMCID: PMC3145394  PMID: 21498624
aged; apolipoprotein E2; apolipoprotein E3; apolipoprotein E4; apolipoproteins E; longevity; meta-analysis; multicenter study
24.  The abcc6a Gene is Required for Normal Zebrafish Development 
Pseudoxanthoma elasticum (PXE) is caused by mutations in the ABCC6 gene, which encodes a putative efflux pump, ABCC6. The zebrafish (Danio rerio) has two ABCC6-related sequences. To study the function of abcc6 during zebrafish development, the mRNA expression levels were measured using RT-PCR and in situ hybridization. The abcc6a showed a relatively high level of expression at 5 days post-fertilization (dpf) and the expression was specific to the Kupffer’s vesicles. The abcc6b expression was evident at 6 hpf and remained high up to 8 dpf, corresponding to embryonic kidney proximal tubules. Morpholinos were designed to both genes to block translation and to prevent pre-mRNA splicing. Injection of the abcc6a morpholinos into 1–4 cell zebrafish embryos decreased gene expression by 54 to 81%, and induced a phenotype, cardiac edema and curled tail associated with death at around 8 dpf. Microinjecting zebrafish embryos with full-length mouse Abcc6 mRNA together with the morpholino completely rescued this phenotype. No phenotypic changes were observed when the abcc6b gene morpholino was injected to embryos, with knock-down efficiency of 100%. These results suggest that abcc6a is an essential gene for normal zebrafish development and provide novel insight into the function of ABCC6, the gene mutated in PXE.
PMCID: PMC3357064  PMID: 20596085
Zebrafish model; Morpholino “knock-down”; Pseudoxanthoma elasticum
25.  Analysis of the ABCA4 Gene by Next-Generation Sequencing 
The authors conducted comprehensive analysis of an important and very variable eye disease gene, ABCA4, by next-generation sequencing in a large cohort of patients and follow-up analysis of identified mutations in both coding and noncoding regions of the ABCA4 locus.
To find all possible disease-associated variants in coding sequences of the ABCA4 gene in a large cohort of patients diagnosed with ABCA4-associated diseases.
One hundred sixty-eight patients who had been clinically diagnosed with Stargardt disease, cone-rod dystrophy, and other ABCA4-associated phenotypes were prescreened for mutations in ABCA4 with the ABCA4 microarray, resulting in finding 1 of 2 expected mutations in 111 patients and 0 of 2 mutations in 57 patients. The next-generation sequencing (NGS) strategy was applied to these patients to sequence the entire coding region and the splice sites of the ABCA4 gene. Identified new variants were confirmed or rejected by Sanger sequencing and analyzed for possible pathogenicity by in silico programs and, where possible, by segregation analyses.
Sequencing was successful in 159 of 168 patients and identified the second disease-associated allele in 49 of 103 (∼48%) of patients with one previously identified mutation. Among those with no mutations, both disease-associated alleles were detected in 4 of 56 patients, and one mutation was detected in 10 of 56 patients. The authors detected a total of 57 previously unknown, possibly pathogenic, variants: 29 missense, 4 nonsense, 9 small deletions and 15 splice-site-altering variants. Of these, 55 variants were deemed pathogenic by a combination of predictive methods and segregation analyses.
Many mutations in the coding sequences of the ABCA4 gene are still unknown, and many possibly reside in noncoding regions of the ABCA4 locus. Although the ABCA4 array remains a good first-pass screening option, the NGS platform is a time- and cost-efficient tool for screening large cohorts.
PMCID: PMC3208189  PMID: 21911583

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