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.
Human microbiome; Oral and gastrointestinal cancer; Assay; Epidemiology
To investigate the relationship between non-steroidal anti-inflammatory drug (NSAID) use and the incidence of benign prostatic hyperplasia (BPH)-related outcomes and nocturia, a lower urinary tract symptom (LUTS) of BPH, in light of accumulating evidence suggesting a role for inflammation in BPH/LUTS development.
Patients and methods
At baseline, participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial completed questions on recent, regular aspirin and ibuprofen use, BPH surgery, diagnosis of an enlarged prostate/BPH, and nocturia. Participants in the intervention arm also underwent a digital rectal examination (DRE), from which prostate dimensions were estimated, as well as a prostate-specific antigen (PSA) test. Only participants in the intervention arm without BPH/LUTS at baseline were included in the analysis (n = 4771).
During follow-up, participants underwent annual DREs and PSA tests, provided annual information on finasteride use, and completed a supplemental questionnaire in 2006–2008 that included additional questions on diagnosis of an enlarged prostate/BPH and nocturia.
Information collected was used to investigate regular aspirin or ibuprofen use in relation to the incidence of six BPH/LUTS definitions: diagnosis of an enlarged prostate/BPH, nocturia (waking two or more times per night to urinate), finasteride use, any self-reported BPH/LUTS, prostate enlargement (estimated prostate volume ≥ 30 mL on any follow-up DRE) and elevation in PSA level (> 1.4 ng/mL on any follow-up PSA test).
Generally, null results were observed for any recent, regular aspirin or ibuprofen use (risk ratio = 0.92–1.21, P = 0.043–0.91) and frequency of use (risk ratio for one category increase in NSAID use = 0.98–1.11, P-trends = 0.10–0.99) with incident BPH/LUTS.
The findings obtained in the present study do not support a protective role for recent NSAID use in BPH/LUTS development.
aspirin; benign prostatic hyperplasia; ibuprofen; lower urinary tract symptoms; non-steroidal anti-inflammatory drugs
The insulin-like growth factor (IGF) signaling pathway is involved in cell proliferation and differentiation. Elevated serum IGF1 levels have been associated with increased colorectal cancer risk; however, studies of this association with colorectal adenoma are inconclusive. We examined serum IGF1, IGF2, and IGFBP3 levels in relation to risk of advanced colorectal adenoma in a case-control study within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. A total of 764 advanced, left-sided colorectal adenoma cases and 775 controls frequency-matched on gender and ethnicity, without evidence of a left-sided polyp on sigmoidoscopy were included in the current study. Serum levels of IGF1, IGF2, and IGFBP3 were measured using an enzyme linked immunosorbent assay in serum samples collected at baseline. Logistic regression was used to estimate the odds ratios (OR) and 95% confidence intervals (CI) for the associations adjusting for age, race, sex, year of blood draw, body mass index, smoking, and education. Higher IGF1 levels were associated with increased adenoma risk: ORs = 1.58 (95% CI=1.16–2.16), 1.42 (95% CI=1.04–1.93), and 1.80 (95% CI=1.30–2.47) for the second, third, and fourth quartiles, respectively (Ptrend=0.002). Elevated IGF2 levels were also associated with increased adenoma risk (OR=1.43, 95% CI=1.05–1.96 for the fourth vs. first quartile, Ptrend=0.02), but the association was no longer significant after adjustment for IGF1 (Ptrend=0.28). IGFBP3 levels were not associated with adenoma risk. Our analysis showed a significant positive association between circulating IGF1 levels and risk of advanced colorectal adenoma, suggesting that IGF1 is associated with the pivotal precursor to colorectal cancer.
colorectal adenoma; insulin-like growth factor
Alcohol and tobacco consumption are well recognized risk factors for head and neck cancer (HNC). Evidence suggests that genetic predisposition may also play a role. Only a few epidemiologic studies, however, have considered the relation between HNC risk and family history of HNC and other cancers. We pooled individual- level data across 12 case-control studies including 8,967 HNC cases and 13,627 controls. We obtained pooled odds ratios (OR) using fixed and random effect models, and adjusting for potential confounding factors. All statistical tests were two-sided. A family history of HNC in first-degree relatives increased the risk of HNC (OR=1.7, 95% confidence interval, CI, 1.2-2.3). The risk was higher when the affected relative was a sibling (OR=2.2, 95% CI 1.6-3.1) rather than a parent (OR=1.5, 95% CI 1.1-1.8), and for more distal HNC anatomic sites (hypopharynx and larynx). The risk was also higher, or limited to, subjects exposed to tobacco. The OR rose to 7.2 (95% CI 5.5-9.5) among subjects with family history, who were alcohol and tobacco users. A weak but significant association (OR=1.1, 95% CI 1.0-1.2) emerged for family history of other tobacco-related neoplasms, particularly with laryngeal cancer (OR=1.3, 95% CI 1.1-1.5). No association was observed for family history of non-tobacco related neoplasms and the risk of HNC (OR=1.0, 95% CI 0.9-1.1). Familial factors play a role in the etiology of HNC. In both subjects with and without family history of HNC, avoidance of tobacco and alcohol exposure may be the best way to avoid HNC.
Head and neck cancer; family history; pooled analysis; tobacco; alcohol
Epidemiological studies have yielded inconsistent associations between vitamin D status and prostate cancer risk, and few studies have evaluated whether the associations vary by disease aggressiveness. We investigated the association between vitamin D status, as determined by serum 25-hydroxy-vitamin D [25(OH)D] level, and risk of prostate cancer in a case–control study nested within the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial.
The study included 749 case patients with incident prostate cancer who were diagnosed 1 to 8 years after blood draw and 781 control subjects who were frequency-matched by age at cohort entry, time since initial screening, and calendar year of cohort entry. All study participants were selected from the trial screening arm (which includes annual standardized prostate cancer screening). Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) by quintile of 25(OH)D. Statistical tests were two-sided.
No statistically significant trend in overall prostate cancer risk was observed with increasing serum season-standardized 25(OH)D level. However, serum 25(OH)D concentrations greater than the lowest quintile (Q1) associated with increased risk of aggressive (Gleason sum ≥7 or clinical stage III or IV) disease (ORs for Q2 vs Q1 = 1.20, 95% CI = 0.80 to 1.81, for Q3 vs Q1 =1.96, 95% CI = 1.34 to 2.87, for Q4 vs Q1 = 1.61, 95% CI = 1.09 to 2.38, and for Q5 vs Q1 = 1.37, 95% CI = 0.92 to 2.05; Ptrend = .05). The rates of aggressive prostate cancer for increasing quintiles of serum 25(OH)2D were 406, 479, 780, 633, and 544 per 100,000 person-years. In exploratory analyses, these associations with aggressive disease were consistent across subgroups defined by age, family history of prostate cancer, diabetes, body mass index, vigorous physical activity, calcium intake, study center, season of blood collection, and assay batch.
The findings of this large prospective study do not support the hypothesis that vitamin D is associated with decreased risk of prostate cancer; indeed, higher circulating 25(OH)D concentrations may be associated with increased risk of aggressive disease.
25-hydroxy-vitamin D; prostate cancer
Benzene exposure causes acute myeloid leukemia, and hematotoxicity, shown as suppression of mature blood and myeloid progenitor cell numbers. As the leukemia-related aneuploidies monosomy 7 and trisomy 8 previously had been detected in the mature peripheral blood cells of exposed workers, we hypothesized that benzene could cause leukemia through the induction of these aneuploidies in hematopoietic stem and progenitor cells. We measured loss and gain of chromosomes 7 and 8 by fluorescence in situ hybridization in interphase colony-forming unit-granulocyte-macrophage (CFU-GM) cells cultured from otherwise healthy benzene-exposed (n=28) and unexposed (n=14) workers. CFU-GM monosomy 7 and 8 levels (but not trisomy) were significantly increased in subjects exposed to benzene overall, compared to levels in the control subjects (p=0.0055 and p=0.0034, respectively). Levels of monosomy 7 and 8 were significantly increased in subjects exposed to <10 ppm (20%, p=0.0419 and 28%, p=0.0056, respectively) and ≥10 ppm (48%, p=0.0045 and 32%, p=0.0354) benzene, compared with controls, and significant exposure-response trends were detected (ptrend=0.0033 and 0.0057). These data show that monosomies 7 and 8 are produced in a dose-dependent fashion in the blood progenitor cells of workers exposed to benzene and may be mechanistically relevant biomarkers of early effect for benzene and other leukemogens.
Benzene; leukemia; monosomy; hematopoietic progenitor
Periodontitis, the progressive loss of the alveolar bone around the teeth and the major cause of tooth loss in adults, is due to oral microorganisms, including Porphyromonas gingivalis. Periodontitis is associated with a local overly aggressive immune response and a spectrum of systemic effects, but the role of this condition in orodigestive cancers is unclear. We prospectively examined clinically ascertained periodontitis (N = 12 605) and serum IgG immune response to P.gingivalis (N = 7852) in relation to orodigestive cancer mortality among men and women in the National Health and Nutrition Examination Survey III. A detailed oral health exam was conducted from 1988 to 1994 in survey Phases I and II, whereas serum IgG for P.gingivalis was measured from 1991 to 1994 in Phase II only. One hundred and five orodigestive cancer deaths were ascertained through 31 December 2006. Periodontitis (moderate or severe) was associated with increased orodigestive cancer mortality [relative risks (RR) = 2.28, 95% confidence interval (CI) = 1.17–4.45]; mortality risks also increased with increasing severity of periodontal disease (P trend = 0.01). Periodontitis-associated mortality was in excess for colorectal (RR = 3.58; 95% CI = 1.15–11.16) and possibly for pancreatic cancer (RR = 4.56; 95% CI = 0.93–22.29). Greater serum P.gingivalis IgG tended to be associated overall with increased orodigestive cancer mortality (P trend = 0.06); P.gingivalis-associated excess orodigestive mortality was also found for healthy subjects not exhibiting overt periodontal disease (RR = 2.25; 95% CI = 1.23–4.14). Orodigestive cancer mortality is related to periodontitis and to the periodontal pathogen, P.gingivalis, independent of periodontal disease. Porphyromonas gingivalis is a biomarker for microbe-associated risk of death due to orodigestive cancer.
Although recent studies have suggested that tooth loss is positively related to the risk of gastric non-cardia cancer, the underlying oral health conditions potentially responsible for the association remain unknown. We investigated whether clinical and behavioral measures of oral health are associated with the risk of gastric precancerous lesions. We conducted a cross-sectional study of 131 patients undergoing upper gastrointestinal endoscopy. Cases were defined as those with gastric precancerous lesions including intestinal metaplasia or chronic atrophic gastritis on the basis of standard biopsy review. A validated structured questionnaire was administered to obtain information on oral health behaviors. A comprehensive clinical oral health examination was performed on a subset of 91 patients to evaluate for periodontal disease and dental caries experience. A total of 41 (31%) cases of gastric precancerous lesions were identified. Compared with non-cases, cases were significantly more likely to not floss their teeth [odds ratio (OR) = 2.89, 95% confidence interval (CI): 1.09–7.64], adjusting for age, sex, race, body mass index, smoking status, educational attainment and Helicobacter pylori status in serum. Among participants who completed the oral examination, cases (n = 28) were more likely to have a higher percentage of sites with gingival bleeding than non-cases [OR = 2.63, 95% CI: 1.37–5.05 for a standard deviation increase in bleeding sites (equivalent to 19.7%)], independent of potential confounders. Our findings demonstrate that specific oral health conditions and behaviors such as gingival bleeding and tooth flossing are associated with gastric precancerous lesions.
Circulating total cholesterol has been inversely associated with cancer risk; however, the role of reverse causation and the associations for high density lipoprotein (HDL) cholesterol have not been fully characterized. We examined the relationship between serum total and HDL cholesterol and risk of overall and site-specific cancers among 29,093 men in the ATBC Study cohort.
Fasting serum total and HDL cholesterol were assayed at baseline, and 7,545 incident cancers were identified during up to 18 years of follow-up. Multivariable proportional hazards models were conducted to estimate relative risks.
Higher serum total cholesterol concentration was associated with decreased risk of cancer overall (RR for comparing high versus low quintile=0.85, 95%CI=0.79–0.91; P trend < 0.001; >276.7 versus <203.9 mg/dL), and the inverse association was particularly evident for cancers of the lung and liver. These associations were no longer significant, however, when cases diagnosed during the first nine years of follow-up were excluded. Greater HDL cholesterol was also associated with decreased risk of cancer (RR for high versus low quintile=0.89, 95%CI=0.83–0.97; P trend=0.01; >55.3 versus <36.2 mg/dL). The inverse association of HDL cholesterol was evident for cancers of lung, prostate, liver, and the hematopoietic system, and the associations of HDL cholesterol with liver and lung cancers remained after excluding cases diagnosed within 12 years of study entry.
Our findings suggest that prior observations regarding serum total cholesterol and cancer are largely explained by reverse causation. Although chance and reverse causation may explain some of the inverse HDL associations, we cannot rule out some etiologic role for this lipid fraction.
serum; cholesterol; high density lipoprotein cholesterol; cancer; risk; prospective; cohort
Androgens and inflammation have been implicated in the etiology of several cancers, including prostate cancer. Serum androgens have been shown to correlate with markers of inflammation and expression of inflammation-related genes.
In this report, we evaluated associations between 9,932 single nucleotide polymorphisms (SNPs) marking common genetic variants in 774 inflammation-related genes and four serum androgen levels (total testosterone [T], bioavailable T [BioT]; 5α-androstane-3α, 17β-diol glucuronide [3αdiol G], and 4-Androstene-3,17-dione [androstenedione]), in 560 healthy men (median age 64 years) drawn from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Baseline serum androgens were measured by radioimmunoassay. Genotypes were determined as part of the Cancer Genetic Markers of Susceptibility Study genome-wide scan. SNP-hormone associations were evaluated using linear regression of hormones adjusted for age. Gene-based p-values were generated using an adaptive rank truncated product method.
Suggestive associations were observed for two inflammation-related genes and circulating androgen levels (false discovery rate [FDR] q-value<0.1) in both SNP and gene-based tests. Specifically, T was associated with common variants in MMP2 and CD14, with the most significant SNPs being rs893226G>T in MMP2 and rs3822356T>C in CD14 (FDR q-value=0.09 for both SNPs). Other genes implicated in either SNP or gene-based tests were IK with T and BioT, PRG2 with T, and TNFSF9 with androstenedione.
These results suggest possible cross-talk between androgen levels and inflammation pathways, but larger studies are needed to confirm these findings and to further clarify the interrelationship between inflammation and androgens and their effects on cancer risk.
Inflammation; Androgens; Genes; Testosterone; Polymorphism; Single Nucleotide
Red meat consumption has been positively associated with colorectal cancer; however, the biologic mechanism underlying this relationship is not understood. Red meat is a major source of iron, which may play a role in colorectal carcinogenesis via increased crypt cell proliferation, cytotoxicity, and endogenous N-nitrosation. In a nested case-control study within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, we prospectively evaluated multiple iron exposure parameters, including dietary intake and serum measures of iron, ferritin, transferrin, total iron binding capacity (TIBC), and unsaturated iron binding capacity (UIBC) in relation to incident colorectal adenoma in 356 cases and 396 matched, polyp-free controls. We also investigated variation in eight key genes involved in iron homeostasis in relation to colorectal adenoma in an additional series totaling 1,126 cases and 1,173 matched controls. We observed a positive association between red meat intake and colorectal adenoma (odds ratio comparing extreme quartiles [ORq4-q1] = 1.59, 95% confidence interval [CI]: 1.02-2.49, P-trend = 0.03). Serum TIBC and UIBC were inversely associated with colorectal adenoma (ORq4-q1 = 0.57, 95% CI: 0.37-0.88, P-trend = 0.03; and ORq4-q1 = 0.62, 95% CI: 0.40-0.95, P-trend = 0.04, respectively). Colorectal adenoma was not associated with serum ferritin, iron, or transferrin saturation, or with polymorphisms in genes involved in iron homeostasis. Serum TIBC and UIBC, parameters which have a reciprocal relationship with overall iron load, were inversely related to colorectal adenoma, suggesting that individuals with lower iron status have a reduced risk of colorectal adenoma.
Diet; meat; iron; colorectal; adenoma; cancer
We report a genome-wide association study in 10,286 cases and 9,135 controls of European ancestry, in the Cancer Genetic Markers of Susceptibility (CGEMS) initiative, identifying a new association with prostate cancer risk on chromosome 8q24 (rs620861, p=1.3×10-10, heterozygote OR = 1.17, 95% CI 1.10 – 1.24; homozygote OR = 1.33; 95% CI 1.21 – 1.45). This defines a new prostate locus on 8q24, Region 4, previously associated with breast cancer.
Genome-wide association studies have identified prostate cancer susceptibility alleles on chromosome 11q13. As part of the Cancer Genetic Markers of Susceptibility (CGEMS) Initiative, the region flanking the most significant marker, rs10896449, was fine mapped in 10 272 cases and 9123 controls of European origin (10 studies) using 120 common single nucleotide polymorphisms (SNPs) selected by a two-staged tagging strategy using HapMap SNPs. Single-locus analysis identified 18 SNPs below genome-wide significance (P< 10−8) with rs10896449 the most significant (P= 7.94 × 10−19). Multi-locus models that included significant SNPs sequentially identified a second association at rs12793759 [odds ratio (OR) = 1.14, P= 4.76 × 10−5, adjusted P= 0.004] that is independent of rs10896449 and remained significant after adjustment for multiple testing within the region. rs10896438, a proxy of previously reported rs12418451 (r2= 0.96), independent of both rs10896449 and rs12793759 was detected (OR = 1.07, P= 5.92 × 10−3, adjusted P= 0.054). Our observation of a recombination hotspot that separates rs10896438 from rs10896449 and rs12793759, and low linkage disequilibrium (rs10896449–rs12793759, r2= 0.17; rs10896449–rs10896438, r2= 0.10; rs12793759–rs10896438, r2= 0.12) corroborate our finding of three independent signals. By analysis of tagged SNPs across ∼123 kb using next generation sequencing of 63 controls of European origin, 1000 Genome and HapMap data, we observed multiple surrogates for the three independent signals marked by rs10896449 (n= 31), rs10896438 (n= 24) and rs12793759 (n= 8). Our results indicate that a complex architecture underlying the common variants contributing to prostate cancer risk at 11q13. We estimate that at least 63 common variants should be considered in future studies designed to investigate the biological basis of the multiple association signals.
DNA damage is thought to play a critical role in the development of colorectal adenoma. Variation in DNA repair genes may alter their capacity to correct endogenous and exogenous DNA damage. We explored the association between common single-nucleotide polymorphisms (SNPs) in DNA repair genes and adenoma risk with a case–control study nested in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. A total of 1338 left sided, advanced colorectal adenoma cases and 1503 matched controls free of left-sided polyps were included in the study. Using DNA extracted from blood, 3144 tag SNPs in 149 DNA repair genes were successfully genotyped. Among Caucasians, 30 SNPs were associated with adenoma risk at P < 0.01, with four SNPs remaining significant after gene-based adjustment for multiple testing. The most significant finding was for a non-synonymous SNP (rs9350) in Exonuclease-1 (EXO1) [odds ratio (OR) = 1.30, 95% confidence interval (CI) = 1.11–1.51, P = 0.001)], which was predicted to be damaging using bioinformatics methods. However, the association was limited to smokers with a strong risk for current smokers (OR = 2.15, 95% CI = 1.27–3.65) and an intermediate risk for former smokers (OR = 1.45, 95% CI = 1.14–1.82) and no association for never smokers (OR = 0.98, 95% CI = 0.76–1.25) (Pinteraction = 0.002). Among the top findings, an SNP (rs17503908) in ataxia telangiectasia mutated (ATM) was inversely related to adenoma risk (OR = 0.75, 95% CI = 0.63–0.91). The association was restricted to never smokers (OR = 0.55, 95% CI = 0.40–0.76) with no increased risk observed among smokers (OR = 0.89, 95% CI = 0.70–1.13) (Pinteraction = 0.006). This large comprehensive study, which evaluated all presently known DNA repair genes, suggests that polymorphisms in EXO1 and ATM may be associated with risk for advanced colorectal adenoma with the associations modified by tobacco-smoking status.
Background Previously, we have shown that increasing adult height is associated with increased risk of testicular germ-cell tumor (TGCT). Recently, a number of single nucleotide polymorphisms (SNPs) have been found to be related to height. We examined whether these SNPs were associated with TGCT and whether they explained the relationship between height and TGCT.
Methods We genotyped 15 height-related SNPs in the US Servicemen’s Testicular Tumor Environmental and Endocrine Determinants (STEED) case–control study. DNA was extracted from buccal cell samples and Taqman assays were used to type the selected SNPs. We used logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs).
Results There were 561 cases and 676 controls for analysis. Two SNPs were found to be associated with risk of TGCT, rs6060373 (CC vs TT, OR = 1.51, 95% CI: 1.06–2.15) and rs143384 (CC vs TT, OR = 1.53, 95% CI: 1.09–2.15). rs6060373 is an intronic polymorphism of ubiquinol-cytochrome c reductase complex chaperone (UQCC), and rs143384 is a 5′UTR polymorphism of growth differentiation factor 5 (GDF5). No individual SNP attenuated the association between height and TGCT. Adjustment for all SNPs previously associated with adult height reduced the associations between adult height and TGCT by ~8.5%, although the P-value indicated only weak evidence that this difference was important (P = 0.26).
Conclusions This novel analysis provides tentative evidence that SNPs which are associated with adult height may also share an association with risk of TGCT.
Body height; case–control studies; epidemiology; polymorphism; single nucleotide; testicular neoplasms
Patients with head and neck squamous cell carcinoma (HNSCC) are at significantly elevated risk of second primary malignancies (SPM), most commonly within the head and neck, lung, and esophagus (HNLE). Our objectives were to quantify the excess risk of SPM across all anatomic sites in which SPM risk is meaningfully elevated, including non-HNLE sites, in a large cohort of US patients.
Population-based analysis of 75,087 patients with HNSCC in the SEER program, quantifying excess SPM risk by integrating relative (standardized incidence ratio; SIR) and absolute (excess absolute risk per 10,000 person-years at risk; EAR) statistics.
In HNSCC patients, the SIR of a second primary solid cancer was 2.2 (95% CI 2.1–2.2), corresponding to EAR of 167.7 additional cases per 10,000 person-years at risk. Over 1 year, 60 patients would need to be followed to observe one excess SPM. Lung cancer burden was most markedly elevated in absolute terms (EAR = 75.2), followed by HN (EAR = 59.8), esophageal (EAR = 14.2), and colorectal (EAR = 4.3) cancers. Lesser but significant excess risks were also observed for cancers of the bladder, liver, stomach, pancreas, kidney, salivary glands, nasopharynx, uterine cervix, and lymphoma.
Data from a large population-based US cohort reveals that HNSCC patients experience markedly excess risk of SPM, predominantly in the HNLE sites. Furthermore, the risk of SPM is also meaningfully elevated, although to a lesser degree, in multiple other tobacco-associated sites.
Second primary; Malignancy; Cancer; Head and neck; Lung; Esophagus; Colon
Case-control studies have shown that regular use of nonsteroidal antiinflammatory drugs (NSAIDs) decreases bladder cancer risk, but few cohort studies have evaluated this association. The authors investigated NSAID use and bladder cancer in 3 large prospective studies (NIH-AARP Diet and Health Study; Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial; and U.S. Radiologic Technologists Study). Frequency of aspirin and nonaspirin NSAID use 1 year prior to baseline was ascertained using self-administered questionnaires. Study-specific hazard ratios and 95% confidence intervals were estimated using Cox regression models and were combined using a fixed-effects meta-analytic model. Data from all studies were aggregated, and aggregated hazard ratios were estimated. The analysis included 508,842 individuals, with 2,489 incident cases of bladder cancer. A reduction in risk was observed for individuals who reported regular use (>2 times/week) of nonaspirin NSAIDs compared with those who reported no use (hazard ratio (HR) = 0.92, 95% confidence interval (CI): 0.81, 1.04). The risk reduction was limited to nonsmokers (HR = 0.58, 95% CI: 0.41, 0.83) (Ptrend = 0.008) (Pinteraction = 0.02). No association was observed between regular aspirin use and bladder cancer risk (HR = 1.04, 95% CI: 0.94, 1.15). Results suggest that nonaspirin NSAIDs, but not aspirin, are associated with a reduction in risk of bladder cancer, particularly for nonsmokers.
anti-inflammatory agents, non-steroidal; aspirin; meta-analysis; urinary bladder neoplasms
Inflammation is hypothesized to play a role in colorectal tumorigenesis. Circulating levels of C-reactive protein (CRP), a serologic marker of the inflammatory response, have been positively associated with colorectal cancer development in some studies; however, there are limited data on the relation of CRP with colorectal adenomas, established precursors of colorectal cancer.
A nested case-control investigation of CRP levels and incident colorectal adenoma was conducted in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, a randomized trial of 154,942 individuals designed to test the efficacy of flexible sigmoidoscopy on colorectal cancer mortality when performed once, and then repeated 3-5 years later. Serum CRP levels were measured in baseline blood specimens from participants who were free of polyps in the left-sided colorectum at the baseline screening procedure, but who were found at the subsequent screen to have at least one colorectal adenoma(N=356), and in a set of polyp-free, frequency-matched controls(N=396).
In a multivariable logistic regression model that included established colorectal adenoma risk factors, a 1-unit increase in log CRP level was associated with a 15% reduction in risk of developing colorectal adenoma (OR=0.85, 95%CI, 0.75-0.98, Ptrend=0.01). This association did not differ according to body size, smoking behavior, gender, use of non-steroidal anti-inflammatory drugs, or adenoma location.
High circulating CRP levels may be protective against colorectal adenoma development.
Though at contrast with mechanistic data on inflammation and colorectal tumorigenesis, this finding is not inconsistent with prior results on CRP and colorectal adenoma and warrants further investigation.
Genome-wide association studies (GWAS) have identified multiple novel prostate cancer predisposition loci. Whether these common genetic variants are associated with incident metastatic prostate cancer or with recurrence after surgical treatment for clinically localized prostate cancer is uncertain.
Twelve SNPs were selected for study in relation to prostate metastatic cancer and recurrence, based on their genome-wide association with prostate cancer in the Cancer Genetic Markers of Susceptibility (CGEMS) (1, 2). To assess risk for metastatic disease, we compared genotypes for the 12 SNPs by logistic regression of 470 incident metastatic prostate cancer cases and 1945 controls in 3 case-control studies. To assess the relationship of these SNPs to risk for prostate cancer recurrence, we used Cox regression in a cohort of 1412 men treated for localized prostate cancer, including 328 recurrences, and used logistic regression in a case-case study, comparing 450 recurrent versus 450 nonrecurrent prostate cancer cases. Study-specific RRs for risk of metastatic disease and recurrence were summarized using meta-analysis, with inverse variance weights.
MSMB rs10993994 (per variant allele summary RR=1.24, 95% CI=1.05-1.48), 8q24 rs4242382 (RR=1.40, 95% CI=1.13-1.75) and 8q24 rs6983267 (RR=0.67, 95% CI=0.50-0.89) were associated with risk for metastatic prostate cancer. None of the 12 SNPs was associated with prostate cancer recurrence.
SNPs in MSMB and 8q24 which predispose to prostate cancer overall are associated with risk for metastatic prostate cancer, the most lethal form of this disease. SNPs predictive of prostate cancer recurrence were not identified, among the predisposition SNPs. GWAS specific to these two phenotypes may identify additional phenotype-specific genetic determinants.
Patients with head and neck squamous cell carcinoma (HNSCC) are at elevated risk of second primary malignancies (SPM), most commonly of the head and neck (HN), lung, and esophagus. Our objectives were to identify HNSCC subsite-specific differences in SPM risk and distribution and to describe trends in risk over 3 decades, before and during the era of human papillomavirus (HPV) –associated oropharyngeal SCC.
Population-based cohort study of 75,087 patients with HNSCC in the Surveillance, Epidemiology, and End Results (SEER) program. SPM risk was quantified by using standardized incidence ratios (SIRs), excess absolute risk (EAR) per 10,000 person-years at risk (PYR), and number needed to observe. Trends in SPM risk were analyzed by using joinpoint log-linear regression.
In patients with HNSCC, the SIR of second primary solid tumor was 2.2 (95% CI, 2.1 to 2.2), and the EAR was 167.7 cancers per 10,000 PYR. The risk of SPM was highest for hypopharyngeal SCC (SIR, 3.5; EAR, 307.1 per 10,000 PYR) and lowest for laryngeal SCC (SIR, 1.9; EAR, 147.8 per 10,000 PYR). The most common SPM site for patients with oral cavity and oropharynx SCC was HN; for patients with laryngeal and hypopharyngeal cancer, it was the lung. Since 1991, SPM risk has decreased significantly among patients with oropharyngeal SCC (annual percentage change in EAR, −4.6%; P = .03).
In patients with HNSCC, the risk and distribution of SPM differ significantly according to subsite of the index cancer. Before the 1990s, hypopharynx and oropharynx cancers carried the highest excess risk of SPM. Since then, during the HPV era, SPM risk associated with oropharyngeal SCC has declined to the lowest risk level of any subsite.
Background: Occupational exposure to nickel (Ni) is associated with an increased risk for lung and nasal cancers. Ni compounds exhibit weak mutagenic activity, cause gene amplification, and disrupt cellular epigenetic homeostasis. However, the Ni-induced changes in global histone modification levels have only been tested in vitro.
Objective: This study was conducted in a Chinese population to determine whether occupational exposure to Ni is associated with alterations of global histone modification levels and to evaluate the inter- and intraindividual variance of global histone modification levels.
Method: Forty-five subjects with occupational exposure to Ni and 75 referents were recruited. Urinary Ni and global H3K4 trimethylation, H3K9 acetylation, and H3K9 dimethylation levels were measured in peripheral blood mononuclear cells (PBMCs) of subjects.
Results: H3K4me3 was elevated in Ni-exposed subjects (0.25% ± 0.11%) compared with referents (0.15% ± 0.04%; p = 0.0004), and H3K9me2 was decreased (Ni-exposed subjects, 0.11% ± 0.05%; referents, 0.15% ± 0.04%; p = 0.003). H3K4me3 was positively (r = 0.4, p = 0.0008) and H3K9ac was negatively (r = 0.1, p = 0.01) associated with urinary Ni. Interindividual variances of H3K4me3, H3K9ac, and H3K9me2 were larger compared with intraindividual variance in both exposure test groups, resulting in reliability coefficients (an estimate of consistency of a set of measurements) of 0.60, 0.67, and 0.79 for H3K4me3, H3K9ac, and H3K9me2, respectively, for Ni-exposed subjects and of 0.75, 0.74, and 0.97, respectively, for referent subjects.
Conclusion: The results of this study indicate that occupational exposure to Ni is associated with alterations of global histone modification levels and that measurements of global levels of histone modifications are relatively stable over time in human PBMCs.
epigenetics; H3K4 trimethylation; H3K9 acetylation; H3K9 dimethylation; histone modifications; interindividual variation; intraindividual variation; nickel; nickel refinery workers
Mutagen challenge and DNA repair assays have been used in case–control studies for nearly three decades to assess human cancer risk. The findings still engender controversy because blood was drawn after cancer diagnosis so the results may be biased, a type called ‘reverse causation’. We therefore used Epstein–Barr virus-transformed lymphoblastoid cell lines established from prospectively collected peripheral blood samples to evaluate lung cancer risk in relation to three DNA repair assays: alkaline Comet assay, host cell reactivation (HCR) assay with the mutagen benzo[a]pyrene diol epoxide and the bleomycin mutagen sensitivity assay. Cases (n = 117) were diagnosed with lung cancer between 0.3 and 6 years after blood collection and controls (n = 117) were frequency matched on calendar year and age at blood collection, gender and smoking history; all races were included. Case and control status was unknown to laboratory investigators. In unconditional logistic regression analyses, statistically significantly increased lung cancer odds ratios (ORadjusted) were observed for bleomycin mutagen sensitivity as quartiles of chromatid breaks/cell [relative to the lowest quartile, OR = 1.2, 95% confidence interval (CI): 0.5–2.5; OR = 1.4, 95% CI: 0.7–3.1; OR = 2.1, 95% CI: 1.0–4.4, respectively, Ptrend = 0.04]. The magnitude of the association between the bleomycin assay and lung cancer risk was modest compared with those reported in previous lung cancer studies but was strengthened when we included only incident cases diagnosed more than a year after blood collection (Ptrend = 0.02), supporting the notion the assay may be a measure of cancer susceptibility. The Comet and HCR assays were unrelated to lung cancer risk.
Telomeres cap chromosome ends and are critical for genomic stability. Many telomere-associated proteins are important for telomere length maintenance. Recent genome-wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) in genes encoding telomere-associated proteins (RTEL1 and TERT-CLPTM1) as markers of cancer risk. We conducted an association study of telomere length and 743 SNPs in 43 telomere biology genes. Telomere length in peripheral blood DNA was determined by Q-PCR in 3,646 participants from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial and Nurses' Health Study. We investigated associations by SNP, gene, and pathway (functional group). We found no associations between telomere length and SNPs in TERT-CLPTM1L or RTEL1. Telomere length was not significantly associated with specific functional groups. Thirteen SNPs from four genes (MEN1, MRE11A, RECQL5, and TNKS) were significantly associated with telomere length. The strongest findings were in MEN1 (Gene-based P=0.006), menin, which associates with the telomerase promoter and may negatively regulate telomerase. This large association study did not find strong associations with telomere length. The combination of limited diversity and evolutionary conservation suggest that these genes may be under selective pressure. More work is needed to explore the role of genetic variants in telomere length regulation.
Telomere length; single-nucleotide polymorphism; SNP; telomere biology; epidemiology
While germline mutations in the adenomatous polyposis coli (APC) gene cause the hereditary colon cancer syndrome (Familial Adenomatous Polyposis), the role of common germline APC variants in sporadic adenomatous polyposis remains unclear. We studied the association of eight APC SNPs, possibly associated with functional consequences, and previously identified gene-environment (dietary fat intake and hormone replacement therapy (HRT) use) interactions, in relation to advanced colorectal adenoma in 758 cases and 767 sex- and race-matched controls, randomly selected from the screening arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Cases had at least one verified advanced adenoma of the distal colon; controls, a negative sigmoidoscopy. We did not observe an association between genotypes for any of the eight APC SNPs and advanced distal adenoma risk (Pglobal gene-based =0.92). Frequencies of identified common haplotypes did not differ between cases and controls (Pglobal haplotype test =0.97). However, the risk for advanced distal adenoma was three-fold higher for one rare haplotype (cases:2.7%;controls:1.6%) (odds ratio = 3.27; 95 percent confidence interval =1.08–9.88). The genetic association between D1822V and advanced distal adenoma was confined to persons consuming a high-fat diet (Pinteraction=0.03). Similar interactions were not observed with HRT use. In our large, nested case-control study of advanced distal adenoma and clinically-verified adenoma-free controls, we observed no association between specific APC SNPs and advanced adenoma. Fat intake modified the APC D1822V-adenoma association, but further studies are warranted.
adenomatous polyposis coli; SNPs; advanced adenoma