Common germline polymorphisms associated with breast cancer-specific survival

INTRODUCTION

Previous studies have identified common germline variants nominally associated with breast cancer survival. These associations have not been widely replicated in further studies. The purpose of this study was to evaluate the association of previously reported SNPs with breast cancer-specific survival using data from a pooled analysis of eight breast cancer survival genome-wide association studies (GWAS) from the Breast Cancer Association Consortium.

METHODS

A literature review was conducted of all previously published associations between common germline variants and three survival outcomes: breast cancer-specific survival, overall survival and disease-free survival. All associations that reached the nominal significance level of P value <0.05 were included. Single nucleotide polymorphisms that had been previously reported as nominally associated with at least one survival outcome were evaluated in the pooled analysis of over 37,000 breast cancer cases for association with breast cancer-specific survival. Previous associations were evaluated using a one-sided test based on the reported direction of effect.

RESULTS

Fifty-six variants from 45 previous publications were evaluated in the meta-analysis. Fifty-four of these were evaluated in the full set of 37,954 breast cancer cases with 2,900 events and the two additional variants were evaluated in a reduced sample size of 30,000 samples in order to ensure independence from the previously published studies. Five variants reached nominal significance (P <0.05) in the pooled GWAS data compared to 2.8 expected under the null hypothesis. Seven additional variants were associated (P <0.05) with ER-positive disease.

CONCLUSIONS

Although no variants reached genome-wide significance (P <5 x 10(-8)), these results suggest that there is some evidence of association between candidate common germline variants and breast cancer prognosis. Larger studies from multinational collaborations are necessary to increase the power to detect associations, between common variants and prognosis, at more stringent significance levels.

Does a Recent Cancer Diagnosis Predict Smoking Cessation? An Analysis From a Large Prospective US Cohort

PURPOSE

Quitting smoking provides important health benefits to patients with cancer. A cancer diagnosis may motivate quitting-potentially providing a teachable moment in which oncologists can encourage and assist patients to quit-but little is known about whether a recent cancer diagnosis (including diagnosis of a cancer that is less strongly linked to smoking) is associated with increased quitting.

METHODS

Cancer Prevention Study-II Nutrition Cohort participants reported smoking status at enrollment in 1992 to 1993 and approximately biennially through 2009. Quit rates of smokers diagnosed with cancer during 2- and 4-year intervals were compared with those of smokers not diagnosed with cancer (12,182 and 12,538 smokers in 2- and 4-year analyses, respectively). Cancers likely to cause physical limitations or symptoms that could influence smoking (cancers of the lung, head and neck, esophagus, or any metastatic cancer) were excluded. Logistic regressions calculated quit rates controlling for age, sex, survey year, cardiovascular disease, and chronic obstructive pulmonary disease.

RESULTS

The 2-year quit rate was higher among the 772 smokers who were diagnosed with cancer (31.3%; 95% CI, 28.0% to 34.5%) than among smokers not diagnosed with cancer (19.5%; 95% CI, 19.0% to 19.9%). A similar difference was observed for 4-year quit rates (43.0% v 33.8%). Results were similar by cancer site and stage.

CONCLUSION

A diagnosis of cancer, even a cancer not strongly related to smoking and with a relatively good prognosis, may be associated with increased quitting that is sustained well after diagnosis. Results support the hypothesis that a cancer diagnosis presents a teachable moment that can be capitalized on to promote cessation.

Genome-wide association analysis of more than 120,000 individuals identifies 15 new susceptibility loci for breast cancer

Genome-wide association studies (GWAS) and large-scale replication studies have identified common variants in 79 loci associated with breast cancer, explaining ∼14% of the familial risk of the disease. To identify new susceptibility loci, we performed a meta-analysis of 11 GWAS, comprising 15,748 breast cancer cases and 18,084 controls together with 46,785 cases and 42,892 controls from 41 studies genotyped on a 211,155-marker custom array (iCOGS). Analyses were restricted to women of European ancestry. We generated genotypes for more than 11 million SNPs by imputation using the 1000 Genomes Project reference panel, and we identified 15 new loci associated with breast cancer at P < 5 × 10(-8). Combining association analysis with ChIP-seq chromatin binding data in mammary cell lines and ChIA-PET chromatin interaction data from ENCODE, we identified likely target genes in two regions: SETBP1 at 18q12.3 and RNF115 and PDZK1 at 1q21.1. One association appears to be driven by an amino acid substitution encoded in EXO1.

A genome-wide pleiotropy scan for prostate cancer risk

BACKGROUND

No single-nucleotide polymorphisms (SNPs) specific for aggressive prostate cancer have been identified in genome-wide association studies (GWAS).

OBJECTIVE

To test if SNPs associated with other traits may also affect the risk of aggressive prostate cancer.

DESIGN, SETTING, AND PARTICIPANTS

SNPs implicated in any phenotype other than prostate cancer (p≤10(-7)) were identified through the catalog of published GWAS and tested in 2891 aggressive prostate cancer cases and 4592 controls from the Breast and Prostate Cancer Cohort Consortium (BPC3). The 40 most significant SNPs were followed up in 4872 aggressive prostate cancer cases and 24,534 controls from the Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome (PRACTICAL) consortium.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Odds ratios (ORs) and 95% confidence intervals (CIs) for aggressive prostate cancer were estimated.

RESULTS AND LIMITATIONS

A total of 4666 SNPs were evaluated by the BPC3. Two signals were seen in regions already reported for prostate cancer risk. rs7014346 at 8q24.21 was marginally associated with aggressive prostate cancer in the BPC3 trial (p=1.6×10(-6)), whereas after meta-analysis by PRACTICAL the summary OR was 1.21 (95% CI 1.16-1.27; p=3.22×10(-18)). rs9900242 at 17q24.3 was also marginally associated with aggressive disease in the meta-analysis (OR 0.90, 95% CI 0.86-0.94; p=2.5×10(-6)). Neither of these SNPs remained statistically significant when conditioning on correlated known prostate cancer SNPs. The meta-analysis by BPC3 and PRACTICAL identified a third promising signal, marked by rs16844874 at 2q34, independent of known prostate cancer loci (OR 1.12, 95% CI 1.06-1.19; p=4.67×10(-5)); it has been shown that SNPs correlated with this signal affect glycine concentrations. The main limitation is the heterogeneity in the definition of aggressive prostate cancer between BPC3 and PRACTICAL.

CONCLUSIONS

We did not identify new SNPs for aggressive prostate cancer. However, rs16844874 may provide preliminary genetic evidence on the role of the glycine pathway in prostate cancer etiology.

PATIENT SUMMARY

We evaluated whether genetic variants associated with several traits are linked to the risk of aggressive prostate cancer. No new such variants were identified.

Reproductive factors, exogenous hormone use and risk of hepatocellular carcinoma among US women: results from the Liver Cancer Pooling Project

BACKGROUND

Hepatocellular carcinoma (HCC) occurs less commonly among women than men in almost all regions of the world. The disparity in risk is particularly notable prior to menopause suggesting that hormonal exposures during reproductive life may be protective. Exogenous oestrogenic exposures such as oral contraceptives (OCs), however, have been reported to increase risk, suggesting that estrogens may be hepatocarcinogenic. To examine the effects of reproductive factors and exogenous hormones on risk, we conducted a prospective analysis among a large group of US women.

METHODS

In the Liver Cancer Pooling Project, a consortium of US-based cohort studies, data from 799,500 women in 11 cohorts were pooled and harmonised. Cox proportional hazards regression models were used to generate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of reproductive factors and exogenous hormones with HCC (n=248).

RESULTS

Bilateral oophorectomy was associated with a significantly increased risk of HCC (HR=2.67, 95% CI=1.22-5.85), which did not appear to be related to a shorter duration of exposure to endogenous hormones or to menopausal hormone therapy use. There was no association between OC use and HCC (HR=1.12, 95% CI=0.82-1.55). Nor were there associations with parity, age at first birth, age at natural menopause, or duration of fertility.

CONCLUSIONS

The current study suggests that bilateral oophorectomy increases the risk of HCC but the explanation for the association is unclear. There was no association between OC use and HCC risk. Examination of endogenous hormone levels in relation to HCC may help to clarify the findings of the current study.

Intakes of caffeine, coffee and tea and risk of amyotrophic lateral sclerosis: Results from five cohort studies

Caffeine is thought to be neuroprotective by antagonizing the adenosine A2A receptors in the brain and thereby protecting motor neurons from excitotoxicity. We examined the association between consumption of caffeine, coffee and tea and risk of amyotrophic lateral sclerosis (ALS). Longitudinal analyses based on over 1,010,000 males and females in five large cohort studies (the Nurses' Health Study, the Health Professionals Follow-up Study, the Cancer Prevention Study II Nutrition Cohort, the Multiethnic Cohort Study, and the National Institutes of Health-AARP Diet and Health Study). Cohort-specific multivariable-adjusted risk ratios (RR) and 95% confidence intervals (CI) estimates of ALS incidence or death were estimated by Cox proportional hazards regression and pooled using random-effects models. Results showed that a total of 1279 cases of ALS were documented during a mean of 18 years of follow-up. Caffeine intake was not associated with ALS risk; the pooled multivariable-adjusted RR comparing the highest to the lowest quintile of intake was 0.96 (95% CI 0.81-1.16). Similarly, neither coffee nor tea was associated with ALS risk. In conclusion, the results of this large study do not support associations of caffeine or caffeinated beverages with ALS risk.

Active Smoking and Mortality Among Colorectal Cancer Survivors: The Cancer Prevention Study II Nutrition Cohort

Purpose

Active smoking is associated with higher colorectal cancer risk, but its association with survival after colorectal cancer diagnosis is unclear. We investigated associations of smoking, before and after diagnosis, with all-cause and colorectal cancer–specific mortality among colorectal cancer survivors.

Patients and Methods

From a cohort of adults who were initially free of colorectal cancer, we identified 2,548 persons diagnosed with invasive, nonmetastatic colorectal cancer between baseline (1992 or 1993) and 2009. Vital status and cause of death were determined through 2010. Smoking was self-reported on the baseline questionnaire and updated in 1997 and every 2 years thereafter. Postdiagnosis smoking information was available for 2,256 persons (88.5%).

Results

Among the 2,548 colorectal cancer survivors, 1,074 died during follow-up, including 453 as a result of colorectal cancer. In multivariable-adjusted Cox proportional hazards regression models, prediagnosis current smoking was associated with higher all-cause mortality (relative risk [RR], 2.12; 95% CI, 1.65 to 2.74) and colorectal cancer–specific mortality (RR, 2.14; 95% CI, 1.50 to 3.07), whereas former smoking was associated with higher all-cause mortality (RR, 1.18; 95% CI, 1.02 to 1.36) but not with colorectal cancer–specific mortality (RR, 0.89; 95% CI, 0.72 to 1.10). Postdiagnosis current smoking was associated with higher all-cause (RR, 2.22; 95% CI, 1.58 to 3.13) and colorectal cancer–specific mortality (RR, 1.92; 95% CI, 1.15 to 3.21), whereas former smoking was associated with all-cause mortality (RR, 1.21; 95% CI, 1.03 to 1.42).

Conclusion

This study adds to the existing evidence that cigarette smoking is associated with higher all-cause and colorectal cancer–specific mortality among persons with nonmetastatic colorectal cancer.

Characterization of large structural genetic mosaicism in human autosomes

Analyses of genome-wide association study (GWAS) data have revealed that detectable genetic mosaicism involving large (>2 Mb) structural autosomal alterations occurs in a fraction of individuals. We present results for a set of 24,849 genotyped individuals (total GWAS set II [TGSII]) in whom 341 large autosomal abnormalities were observed in 168 (0.68%) individuals. Merging data from the new TGSII set with data from two prior reports (the Gene-Environment Association Studies and the total GWAS set I) generated a large dataset of 127,179 individuals; we then conducted a meta-analysis to investigate the patterns of detectable autosomal mosaicism (n = 1,315 events in 925 [0.73%] individuals). Restricting to events >2 Mb in size, we observed an increase in event frequency as event size decreased. The combined results underscore that the rate of detectable mosaicism increases with age (p value = 5.5 × 10(-31)) and is higher in men (p value = 0.002) but lower in participants of African ancestry (p value = 0.003). In a subset of 47 individuals from whom serial samples were collected up to 6 years apart, complex changes were noted over time and showed an overall increase in the proportion of mosaic cells as age increased. Our large combined sample allowed for a unique ability to characterize detectable genetic mosaicism involving large structural events and strengthens the emerging evidence of non-random erosion of the genome in the aging population.

Tobacco and alcohol in relation to male breast cancer: an analysis of the male breast cancer pooling project consortium

BACKGROUND

The etiology of male breast cancer is poorly understood, partly due to its relative rarity. Although tobacco and alcohol exposures are known carcinogens, their association with male breast cancer risk remains ill-defined.

METHODS

The Male Breast Cancer Pooling Project consortium provided 2,378 cases and 51,959 controls for analysis from 10 case-control and 10 cohort studies. Individual participant data were harmonized and pooled. Unconditional logistic regression was used to estimate study design-specific (case-control/cohort) ORs and 95% confidence intervals (CI), which were then combined using fixed-effects meta-analysis.

RESULTS

Cigarette smoking status, smoking pack-years, duration, intensity, and age at initiation were not associated with male breast cancer risk. Relations with cigar and pipe smoking, tobacco chewing, and snuff use were also null. Recent alcohol consumption and average grams of alcohol consumed per day were also not associated with risk; only one subanalysis of very high recent alcohol consumption (>60 g/day) was tentatively associated with male breast cancer (ORunexposed referent = 1.29; 95% CI, 0.97-1.71; OR>0-<7 g/day referent = 1.36; 95% CI, 1.04-1.77). Specific alcoholic beverage types were not associated with male breast cancer. Relations were not altered when stratified by age or body mass index.

CONCLUSIONS

In this analysis of the Male Breast Cancer Pooling Project, we found little evidence that tobacco and alcohol exposures were associated with risk of male breast cancer.

IMPACT

Tobacco and alcohol do not appear to be carcinogenic for male breast cancer. Future studies should aim to assess these exposures in relation to subtypes of male breast cancer.

Generalizability of established prostate cancer risk variants in men of African ancestry

Genome-wide association studies have identified more than 80 risk variants for prostate cancer, mainly in European or Asian populations. The generalizability of these variants in other racial/ethnic populations needs to be understood before the loci can be used widely in risk modeling. In our study, we examined 82 previously reported risk variants in 4,853 prostate cancer cases and 4,678 controls of African ancestry. We performed association testing for each variant using logistic regression adjusted for age, study and global ancestry. Of the 82 known risk variants, 68 (83%) had effects that were directionally consistent in their association with prostate cancer risk and 30 (37%) were significantly associated with risk at p < 0.05, with the most statistically significant variants being rs116041037 (p = 3.7 × 10(-26) ) and rs6983561 (p = 1.1 × 10(-16) ) at 8q24, as well as rs7210100 (p = 5.4 × 10(-8) ) at 17q21. By exploring each locus in search of better markers, the number of variants that captured risk in men of African ancestry (p < 0.05) increased from 30 (37%) to 44 (54%). An aggregate score comprised of these 44 markers was strongly associated with prostate cancer risk [per-allele odds ratio (OR) = 1.12, p = 7.3 × 10(-98) ]. In summary, the consistent directions of effects for the vast majority of variants in men of African ancestry indicate common functional alleles that are shared across populations. Further exploration of these susceptibility loci is needed to identify the underlying biologically relevant variants to improve prostate cancer risk modeling in populations of African ancestry.

Multilevel-analysis identify a cis-expression quantitative trait locus associated with risk of renal cell carcinoma

We conducted multilevel analyses to identify potential susceptibility loci for renal cell carcinoma (RCC), which may be overlooked in traditional genome-wide association studies (GWAS). A gene set enrichment analysis was performed utilizing a GWAS dataset comprised of 894 RCC cases and 1,516 controls using GenGen, SNP ratio test, and ALIGATOR. The antigen processing and presentation pathway was consistently significant (P = 0.001, = 0.004, and < 0.001, respectively). Versatile gene-based association study approach was applied to the top-ranked pathway and identified the driven genes. By comparing the expression of the genes in RCC tumor and adjacent normal tissues, we observed significant overexpression of HLA genes in tumor tissues, which was also supported by public databases. We sought to validate genetic variants in antigen processing and presentation pathway in an independent GWAS dataset comprised of 1,311 RCC cases and 3,424 control subjects from the National Cancer Institute; one SNP, rs1063355, was significant in both populations (P_{meta-analysis} = 9.15 × 10⁻⁴, P_{heterogeneity} = 0.427). Strong correlation indicated that rs1063355 was a cis-expression quantitative trait loci which associated with HLA-DQB1 expression (Spearman's rank r = −0.59, p = 5.61 × 10⁻⁶). The correlation was further validated using a public dataset. Our results highlighted the role of immune-related pathway and genes in the etiology of RCC.

Analysis of Multivariate Disease Classification Data in the Presence of Partially Missing Disease Traits

In modern cancer epidemiology, diseases are classified based on pathologic and molecular traits, and different combinations of these traits give rise to many disease subtypes. The effect of predictor variables can be measured by fitting a polytomous logistic model to such data. The differences (heterogeneity) among the relative risk parameters associated with subtypes are of great interest to better understand disease etiology. Due to the heterogeneity of the relative risk parameters, when a risk factor is changed, the prevalence of one subtype may change more than that of another subtype does. Estimation of the heterogeneity parameters is difficult when disease trait information is only partially observed and the number of disease subtypes is large. We consider a robust semiparametric approach based on the pseudo-conditional likelihood for estimating these heterogeneity parameters. Through simulation studies, we compare the robustness and efficiency of our approach with that of the maximum likelihood approach. The method is then applied to analyze the associations of weight gain with risk of breast cancer subtypes using data from the American Cancer Society Cancer Prevention Study II Nutrition Cohort.

Interactions between cigarette smoking and fine particulate matter in the Risk of Lung Cancer Mortality in Cancer Prevention Study II

The International Agency for Research on Cancer recently classified outdoor air pollution and airborne particulate matter as carcinogenic to humans. However, there are gaps in the epidemiologic literature, including assessment of possible joint effects of cigarette smoking and fine particulate matter (particulate matter less than or equal to 2.5 µm in diameter) on lung cancer risk. We present estimates of interaction on the additive scale between these risk factors from Cancer Prevention Study II, a large prospective US cohort study of nearly 1.2 million participants recruited in 1982. Estimates of the relative excess risk of lung cancer mortality due to interaction, the attributable proportion due to interaction, and the synergy index were 2.19 (95% confidence interval (CI): -0.10, 4.83), 0.14 (95% CI: 0.00, 0.25), and 1.17 (95% CI: 1.00, 1.37), respectively, using the 25th and 75th percentiles as cutpoints for fine particulate matter. This suggests small increases in lung cancer risk among persons with both exposures beyond what would be expected from the sum of the effects of the individual exposures alone. Although reductions in cigarette smoking will achieve the greatest impact on lung cancer rates, these results suggest that attempted reductions in lung cancer risk through both tobacco control and air quality management may exceed expectations based on reducing exposure to either risk factor alone.

Imputation and subset-based association analysis across different cancer types identifies multiple independent risk loci in the TERT-CLPTM1L region on chromosome 5p15.33

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.

Artificially and sugar-sweetened carbonated beverage consumption is not associated with risk of lymphoid neoplasms in older men and women

BACKGROUND

Concern about the carcinogenic potential of aspartame was raised after an increase in lymphomas and leukemia was reported in an animal study at doses similar to human exposure. Two prospective cohort studies published after the report found inconsistent results for estimated aspartame intake, artificially sweetened beverage consumption, and risk of lymphoid neoplasms.

OBJECTIVE

The objective of this study was to examine associations of artificially and sugar-sweetened carbonated beverage consumption (for comparison) and aspartame intake with risk of non-Hodgkin lymphoma (NHL) overall and by major histologic subtype in the Cancer Prevention Study-II Nutrition Cohort.

METHODS

Among 100,442 adult men and women who provided information on diet and lifestyle factors in 1999, 1196 NHL cases were verified during a 10-y follow-up period. Cox proportional hazards regression was used to estimate multivariable-adjusted RRs and 95% CIs.

RESULTS

In women and men combined, there were no associations of consumption of ≥1 (355 mL) servings/d of artificially (RR: 0.92; 95% CI: 0.73, 1.17; P-trend: 0.14) or sugar- (RR: 1.10; 95% CI: 0.77, 1.58; P-trend: 0.62) sweetened carbonated beverages with NHL risk, compared to no consumption (P-heterogeneity by gender: 0.11-1.00). Similarly, aspartame intake was not associated with NHL risk (RR: 1.02; 95% CI: 0.84, 1.24; P-trend: 0.69, top vs. bottom quintile). Associations with NHL subtype (multiple myeloma, diffuse large B-cell lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, and follicular and other B-cell lymphoma) were generally null.

CONCLUSION

These findings do not support associations of daily consumption of artificially or sugar-sweetened carbonated beverages, or aspartame, with NHL risk.

Alcohol control efforts in comprehensive cancer control plans and alcohol use among adults in the USA

AIMS

To understand how US cancer control plans address alcohol use, an important but frequently overlooked cancer risk factor, and how many US adults are at risk.

METHODS

We reviewed alcohol control efforts in 69 comprehensive cancer control plans in US states, tribes and jurisdictions. Using the 2011 Behavioral Risk Factor Surveillance System, we assessed the prevalence of current alcohol use among US adults and the proportion of these drinkers who exceeded guidelines for moderate drinking.

RESULTS

Most comprehensive cancer control plans acknowledged alcohol use as a cancer risk factor but fewer than half included a goal, objective or strategy to address alcohol use. More than half of US adults reported current alcohol use in 2011, and two of three drinkers exceeded moderate drinking guidelines at least once in the past month. Many states that did not address alcohol use in comprehensive cancer control plans also had a high proportion of adults at risk.

CONCLUSION

Alcohol use is a common cancer risk factor in the USA, but alcohol control strategies are not commonly included in comprehensive cancer control plans. Supporting the implementation of evidence-based strategies to prevent the excessive use of alcohol is one tool the cancer control community can use to reduce the risk of cancer.

Relationships between fine particulate air pollution, cardiometabolic disorders, and cardiovascular mortality

RATIONALE

Growing evidence suggests that long-term exposure to fine particulate matter (PM2.5) air pollution contributes to risk of cardiovascular disease (CVD) morbidity and mortality. There is uncertainty about who are most susceptible. Individuals with underlying cardiometabolic disorders, including hypertension, diabetes mellitus, and obesity, may be at greater risk. PM2.5 pollution may also contribute to cardiometabolic disorders, augmenting CVD risk.

OBJECTIVE

This analysis evaluates relationships between long-term PM2.5 exposure and cardiometabolic disease on risk of death from CVD and cardiometabolic conditions.

METHODS AND RESULTS

Data on 669 046 participants from the American Cancer Society Cancer Prevention Study II cohort were linked to modeled PM2.5 concentrations at geocoded home addresses. Cox proportional hazards regression models were used to estimate adjusted hazards ratios for death from CVD and cardiometabolic diseases based on death-certificate information. Effect modification by pre-existing cardiometabolic risk factors on the PM2.5-CVD mortality association was examined. PM2.5 exposure was associated with CVD mortality, with the hazards ratios (95% confidence interval) per 10 μg/m(3) increase in PM2.5 equal to 1.12 (1.10-1.15). Deaths linked to hypertension and diabetes mellitus (mentioned on death certificate as either primary or contributing cause of death) were also associated with PM2.5. There was no consistent evidence of effect modification by cardiometabolic disease risk factors on the PM2.5-CVD mortality association.

CONCLUSIONS

Pollution-induced CVD mortality risk is observed for those with and without existing cardiometabolic disorders. Long-term exposure may also contribute to the development or exacerbation of cardiometabolic disorders, increasing risk of CVD, and cardiometabolic disease mortality.

Daily aspirin use and prostate cancer-specific mortality in a large cohort of men with nonmetastatic prostate cancer

PURPOSE

In a recent analysis of a large clinical database, postdiagnosis aspirin use was associated with 57% lower prostate cancer-specific mortality (PCSM) among men diagnosed with nonmetastatic prostate cancer. However, information on this association remains limited. We assessed the association between daily aspirin use and PCSM in a large prospective cohort.

PATIENTS AND METHODS

This analysis included men diagnosed with nonmetastatic prostate cancer between enrollment in the Cancer Prevention Study-II Nutrition Cohort in 1992 or 1993 and June 2009. Aspirin use was reported at enrollment, in 1997, and every 2 years thereafter. During follow-up through 2010, there were 441 prostate cancer deaths among 8,427 prostate cancer cases with information on prediagnosis aspirin use and 301 prostate cancer deaths among 7,118 prostate cancer cases with information on postdiagnosis aspirin use.

RESULTS

Compared with no aspirin use, neither prediagnosis nor postdiagnosis daily aspirin use were statistically significantly associated with PCSM (prediagnosis use, multivariable-adjusted hazard ratio (HR) = 0.92, 95% CI 0.72 to 1.17, postdiagnosis use, HR = 0.98; 95% CI, 0.74 to 1.29). However, among men diagnosed with high-risk cancers (≥ T3 and/or Gleason score ≥ 8), postdiagnosis daily aspirin use was associated with lower PCSM (HR = 0.60; 95% CI, 0.37 to 0.97), with no clear difference by dose (low-dose, typically 81 mg per day, HR = 0.50; 95% CI, 0.27 to 0.92, higher dose, HR = 0.73; 95% CI, 0.40 to 1.34).

CONCLUSION

A randomized trial of aspirin among men diagnosed with nonmetastatic prostate cancer was recently funded. Our results suggest any additional randomized trials addressing this question should prioritize enrolling men with high-risk cancers and need not use high doses.

The 19q12 bladder cancer GWAS signal: association with cyclin E function and aggressive disease

A genome-wide association study (GWAS) of bladder cancer identified a genetic marker rs8102137 within the 19q12 region as a novel susceptibility variant. This marker is located upstream of the CCNE1 gene, which encodes cyclin E, a cell-cycle protein. We performed genetic fine-mapping analysis of the CCNE1 region using data from two bladder cancer GWAS (5,942 cases and 10,857 controls). We found that the original GWAS marker rs8102137 represents a group of 47 linked SNPs (with r(2) ≥ 0.7) associated with increased bladder cancer risk. From this group, we selected a functional promoter variant rs7257330, which showed strong allele-specific binding of nuclear proteins in several cell lines. In both GWASs, rs7257330 was associated only with aggressive bladder cancer, with a combined per-allele OR = 1.18 [95% confidence interval (CI), 1.09-1.27, P = 4.67 × 10(-5)] versus OR = 1.01 (95% CI, 0.93-1.10, P = 0.79) for nonaggressive disease, with P = 0.0015 for case-only analysis. Cyclin E protein expression analyzed in 265 bladder tumors was increased in aggressive tumors (P = 0.013) and, independently, with each rs7257330-A risk allele (P(trend) = 0.024). Overexpression of recombinant cyclin E in cell lines caused significant acceleration of cell cycle. In conclusion, we defined the 19q12 signal as the first GWAS signal specific for aggressive bladder cancer. Molecular mechanisms of this genetic association may be related to cyclin E overexpression and alteration of cell cycle in carriers of CCNE1 risk variants. In combination with established bladder cancer risk factors and other somatic and germline genetic markers, the CCNE1 variants could be useful for inclusion into bladder cancer risk prediction models.

Body mass index and all-cause mortality in a large prospective cohort of white and black U.S. Adults

Remaining controversies on the association between body mass index (BMI) and mortality include the effects of smoking and prevalent disease on the association, whether overweight is associated with higher mortality rates, differences in associations by race and the optimal age at which BMI predicts mortality. To assess the relative risk (RR) of mortality by BMI in Whites and Blacks among subgroups defined by smoking, prevalent disease, and age, 891,572 White and 38,119 Black men and women provided height, weight and other information when enrolled in the Cancer Prevention Study II in 1982. Over 28 years of follow-up, there were 434,400 deaths in Whites and 18,702 deaths in Blacks. Cox proportional-hazards regression was used to estimate multivariable-adjusted relative risks (RR) and 95% confidence intervals (CI). Smoking and prevalent disease status significantly modified the BMI-mortality relationship in Whites and Blacks; higher BMI was most strongly associated with higher risk of mortality among never smokers without prevalent disease. All levels of overweight and obesity were associated with a statistically significantly higher risk of mortality compared to the reference category (BMI 22.5-24.9 kg/m2), except among Black women where risk was elevated but not statistically significant in the lower end of overweight. Although absolute mortality rates were higher in Blacks than Whites within each BMI category, relative risks (RRs) were similar between race groups for both men and women (p-heterogeneity by race  = 0.20 for men and 0.23 for women). BMI was most strongly associated with mortality when reported before age 70 years. Results from this study demonstrate for the first time that the BMI-mortality relationship differs for men and women who smoke or have prevalent disease compared to healthy never-smokers. These findings further support recommendations for maintaining a BMI between 20-25 kg/m2 for optimal health and longevity.

Genome-wide scan of 29,141 African Americans finds no evidence of directional selection since admixture

The extent of recent selection in admixed populations is currently an unresolved question. We scanned the genomes of 29,141 African Americans and failed to find any genome-wide-significant deviations in local ancestry, indicating no evidence of selection influencing ancestry after admixture. A recent analysis of data from 1,890 African Americans reported that there was evidence of selection in African Americans after their ancestors left Africa, both before and after admixture. Selection after admixture was reported on the basis of deviations in local ancestry, and selection before admixture was reported on the basis of allele-frequency differences between African Americans and African populations. The local-ancestry deviations reported by the previous study did not replicate in our very large sample, and we show that such deviations were expected purely by chance, given the number of hypotheses tested. We further show that the previous study's conclusion of selection in African Americans before admixture is also subject to doubt. This is because the FST statistics they used were inflated and because true signals of unusual allele-frequency differences between African Americans and African populations would be best explained by selection that occurred in Africa prior to migration to the Americas.

Evidence for an association of dietary flavonoid intake with breast cancer risk by estrogen receptor status is limited

BACKGROUND

Results from preclinical studies suggest that flavonoids, which are ubiquitous in plant-based diets, lower breast cancer risk. Epidemiologic studies of flavonoid intake and breast cancer risk, however, are limited, and few investigated associations with the more aggressive estrogen receptor (ER)-negative (ER-) tumors.

OBJECTIVE

We examined the associations between 7 subclasses of dietary flavonoids and invasive postmenopausal breast cancer risk overall and by ER status in a U.S. prospective cohort.

METHODS

In 1999-2000, 56,630 postmenopausal women completed detailed self-administered questionnaires, among whom 2116 invasive breast cancers were verified during a mean follow-up period of 8.5 y. Cox proportional hazards regression was used to calculate multivariable-adjusted HRs and 95% CIs.

RESULTS

Total flavonoid intake was not associated with breast cancer risk. However, there was a modest inverse association between flavone intake and overall breast cancer risk (fifth vs. first quintile HR: 0.88; 95% CI: 0.76, 1.01; P-trend = 0.04) and between flavan-3-ol intake and risk of ER- breast cancer (for an increment of 40 mg/d; HR: 0.81; 95% CI: 0.67, 0.97) but not for ER-positive (ER+) breast cancer risk.

CONCLUSION

The inverse association of flavan-3-ol intake with ER- but not ER+ breast cancer is consistent with other studies that suggest a beneficial role of plant-based diets in ER- breast cancer risk.

A meta-analysis of 87,040 individuals identifies 23 new susceptibility loci for prostate cancer

Genome-wide association studies (GWAS) have identified 76 variants associated with prostate cancer risk predominantly in populations of European ancestry. To identify additional susceptibility loci for this common cancer, we conducted a meta-analysis of > 10 million SNPs in 43,303 prostate cancer cases and 43,737 controls from studies in populations of European, African, Japanese and Latino ancestry. Twenty-three new susceptibility loci were identified at association P < 5 × 10(-8); 15 variants were identified among men of European ancestry, 7 were identified in multi-ancestry analyses and 1 was associated with early-onset prostate cancer. These 23 variants, in combination with known prostate cancer risk variants, explain 33% of the familial risk for this disease in European-ancestry populations. These findings provide new regions for investigation into the pathogenesis of prostate cancer and demonstrate the usefulness of combining ancestrally diverse populations to discover risk loci for disease.

Abstract 4143: Oral microbiome and risk of head and neck cancer, a nested case-control study

Introduction: The oral microbiome is intimately involved in inflammatory processes in the oral cavity and may be involved in metabolism of carcinogens in tobacco smoke. Our hypothesis is that oral microbiota may promote head and neck carcinogenesis, possibly related to smoking. To test this hypothesis, we conducted a nested case-control study to prospectively examine the role of the oral microbiome in head and neck cancer, in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial cohort.

Methods: Subjects in the PLCO Trial completed risk factor questionnaires and provided oral wash samples. Trial participants were followed for cancer incidence by annual follow-up, medical chart review and search of mortality databases. During follow-up, 87 histologically confirmed head and neck cancer cases occurred subsequent to oral wash sample collection. We matched these cases to 174 cohort-nested controls (matched by age, gender, and race). DNA was extracted from oral wash samples, 16S rRNA genes were amplified by universal primers, and product was bar-coded and sequenced by 454 FLX technology. 16S rRNA bacterial gene sequences were binned into operational taxonomic units (based on 97% identity) and further assigned to taxonomy in the QIIME pipeline. We performed nonparametric Wilcoxon signed-rank tests and conditional logistic regression to compare differences between head and neck cancer cases and controls, with respect to overall bacterial community structure and relative abundance of specific taxa.

Results: From 261 oral samples, we obtained 2,548,067 high quality 16S rRNA gene sequence reads. Overall community structure, based on a weighted UniFrac phylogenetic distance index, did not differ significantly between cases and controls (p&gt;0.05). The major phyla in controls were Firmicutes (59.5%), Actinobacteria (15.5%), Bacteroidetes (11.3%), Proteobacteria (10.3%), and Fusobacteria (2.8%). Decreased abundance of Proteobacteria was observed in cases (7.8%) compared to controls (Wilcoxon test, p = 0.008, FDR controlled p=0.041). After consideration of age, race and sex in conditional logistic regression analysis, an inverse association of Proteobacteria with head and neck cancer risk was observed in smokers (OR comparing extreme tertiles =0.34, 95% CI 0.15-0.79; ptrend = 0.009 [FDR controlled p=0.065]), but not in non-smokers (ptrend=0.62). We also noted a relative increase in abundance of Bifidobacteriales order (multivariate p=0.002, FDR controlled p=0.045) and Lactobacillaceae family (multivariate p=0.005, FDR controlled p&gt;0.05) in cases compared with controls.

Conclusion: This first prospective study of the oral microbiome and head and neck cancer suggests that Proteobacteria and Bifidobacteriales are related to risk of head and neck cancer. Replication of these first observations is needed.

Citation Format: Jiyoung Ahn, Yingfei Ma, Mark P. Purdue, Neal D. Freedman, Susan M. Gapstur, Liying Yang, Richard B. Hayes, Zhiheng Pei. Oral microbiome and risk of head and neck cancer, a nested case-control study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4143. doi:10.1158/1538-7445.AM2014-4143