A multilayered post-GWAS assessment on genetic susceptibility to pancreatic cancer

BACKGROUND

Pancreatic cancer (PC) is a complex disease in which both non-genetic and genetic factors interplay. To date, 40 GWAS hits have been associated with PC risk in individuals of European descent, explaining 4.1% of the phenotypic variance.

METHODS

We complemented a new conventional PC GWAS (1D) with genome spatial autocorrelation analysis (2D) permitting to prioritize low frequency variants not detected by GWAS. These were further expanded via Hi-C map (3D) interactions to gain additional insight into the inherited basis of PC. In silico functional analysis of public genomic information allowed prioritization of potentially relevant candidate variants.

RESULTS

We identified several new variants located in genes for which there is experimental evidence of their implication in the biology and function of pancreatic acinar cells. Among them is a novel independent variant in NR5A2 (rs3790840) with a meta-analysis p value = 5.91E-06 in 1D approach and a Local Moran's Index (LMI) = 7.76 in 2D approach. We also identified a multi-hit region in CASC8-a lncRNA associated with pancreatic carcinogenesis-with a lowest p value = 6.91E-05. Importantly, two new PC loci were identified both by 2D and 3D approaches: SIAH3 (LMI = 18.24), CTRB2/BCAR1 (LMI = 6.03), in addition to a chromatin interacting region in XBP1-a major regulator of the ER stress and unfolded protein responses in acinar cells-identified by 3D; all of them with a strong in silico functional support.

CONCLUSIONS

This multi-step strategy, combined with an in-depth in silico functional analysis, offers a comprehensive approach to advance the study of PC genetic susceptibility and could be applied to other diseases.

A new efficient method to detect genetic interactions for lung cancer GWAS

BACKGROUND

Genome-wide association studies (GWAS) have proven successful in predicting genetic risk of disease using single-locus models; however, identifying single nucleotide polymorphism (SNP) interactions at the genome-wide scale is limited due to computational and statistical challenges. We addressed the computational burden encountered when detecting SNP interactions for survival analysis, such as age of disease-onset. To confront this problem, we developed a novel algorithm, called the Efficient Survival Multifactor Dimensionality Reduction (ES-MDR) method, which used Martingale Residuals as the outcome parameter to estimate survival outcomes, and implemented the Quantitative Multifactor Dimensionality Reduction method to identify significant interactions associated with age of disease-onset.

METHODS

To demonstrate efficacy, we evaluated this method on two simulation data sets to estimate the type I error rate and power. Simulations showed that ES-MDR identified interactions using less computational workload and allowed for adjustment of covariates. We applied ES-MDR on the OncoArray-TRICL Consortium data with 14,935 cases and 12,787 controls for lung cancer (SNPs = 108,254) to search over all two-way interactions to identify genetic interactions associated with lung cancer age-of-onset. We tested the best model in an independent data set from the OncoArray-TRICL data.

RESULTS

Our experiment on the OncoArray-TRICL data identified many one-way and two-way models with a single-base deletion in the noncoding region of BRCA1 (HR 1.24, P = 3.15 × 10-15), as the top marker to predict age of lung cancer onset.

CONCLUSIONS

From the results of our extensive simulations and analysis of a large GWAS study, we demonstrated that our method is an efficient algorithm that identified genetic interactions to include in our models to predict survival outcomes.

A Transcriptome-Wide Association Study Identifies Novel Candidate Susceptibility Genes for Pancreatic Cancer

BACKGROUND

Although 20 pancreatic cancer susceptibility loci have been identified through genome-wide association studies in individuals of European ancestry, much of its heritability remains unexplained and the genes responsible largely unknown.

METHODS

To discover novel pancreatic cancer risk loci and possible causal genes, we performed a pancreatic cancer transcriptome-wide association study in Europeans using three approaches: FUSION, MetaXcan, and Summary-MulTiXcan. We integrated genome-wide association studies summary statistics from 9040 pancreatic cancer cases and 12 496 controls, with gene expression prediction models built using transcriptome data from histologically normal pancreatic tissue samples (NCI Laboratory of Translational Genomics [n = 95] and Genotype-Tissue Expression v7 [n = 174] datasets) and data from 48 different tissues (Genotype-Tissue Expression v7, n = 74-421 samples).

RESULTS

We identified 25 genes whose genetically predicted expression was statistically significantly associated with pancreatic cancer risk (false discovery rate < .05), including 14 candidate genes at 11 novel loci (1p36.12: CELA3B; 9q31.1: SMC2, SMC2-AS1; 10q23.31: RP11-80H5.9; 12q13.13: SMUG1; 14q32.33: BTBD6; 15q23: HEXA; 15q26.1: RCCD1; 17q12: PNMT, CDK12, PGAP3; 17q22: SUPT4H1; 18q11.22: RP11-888D10.3; and 19p13.11: PGPEP1) and 11 at six known risk loci (5p15.33: TERT, CLPTM1L, ZDHHC11B; 7p14.1: INHBA; 9q34.2: ABO; 13q12.2: PDX1; 13q22.1: KLF5; and 16q23.1: WDR59, CFDP1, BCAR1, TMEM170A). The association for 12 of these genes (CELA3B, SMC2, and PNMT at novel risk loci and TERT, CLPTM1L, INHBA, ABO, PDX1, KLF5, WDR59, CFDP1, and BCAR1 at known loci) remained statistically significant after Bonferroni correction.

CONCLUSIONS

By integrating gene expression and genotype data, we identified novel pancreatic cancer risk loci and candidate functional genes that warrant further investigation.

AHRR methylation in heavy smokers: associations with smoking, lung cancer risk, and lung cancer mortality

BACKGROUND

A low level of methylation at cg05575921 in the aryl-hydrocarbon receptor repressor (AHRR) gene is robustly associated with smoking, and some studies have observed associations between cg05575921 methylation and increased lung cancer risk and mortality. To prospectively examine whether decreased methylation at cg05575921 may identify high risk subpopulations for lung cancer screening among heavy smokers, and mortality in cases, we evaluated associations between cg05575921 methylation and lung cancer risk and mortality, by histotype, in heavy smokers.

METHODS

The β-Carotene and Retinol Efficacy Trial (CARET) included enrollees ages 45-69 with ≥ 20 pack-year smoking histories and/or occupational asbestos exposure. A subset of CARET participants had cg05575921 methylation available from HumanMethylationEPIC assays of blood collected on average 4.3 years prior to lung cancer diagnosis in cases. Cg05575921 methylation β-values were treated continuously for a 10% methylation decrease and as quintiles, where quintile 1 (Q1, referent) represents high methylation and Q5, low methylation. We used conditional logistic regression models to examine lung cancer risk overall and by histotype in a nested case-control study including 316 lung cancer cases (diagnosed through 2005) and 316 lung cancer-free controls matched on age (±5 years), sex, race/ethnicity, enrollment year, current/former smoking, asbestos exposure, and follow-up time. Mortality analyses included 372 lung cancer cases diagnosed between 1985 and 2013 with available methylation data. We used Cox proportional hazards models to examine mortality overall and by histotype.

RESULTS

Decreased cg05575921 methylation was strongly associated with smoking, even in our population of heavy smokers. We did not observe associations between decreased pre-diagnosis cg05575921 methylation and increased lung cancer risk, overall or by histotype. We observed linear increasing trends for lung cancer-specific mortality across decreasing cg05575921 methylation quintiles for adenocarcinoma and small cell carcinoma (P-trends = 0.01 and 0.04, respectively).

CONCLUSIONS

In our study of heavy smokers, decreased cg05575921 methylation was strongly associated with smoking but not increased lung cancer risk. The observed association between cg05575921 methylation and increased mortality in adenocarcinoma and small cell histotypes requires further examination. Our results do not support using decreased cg05575921 methylation as a biomarker for lung cancer screening risk stratification.

Abstract A20: AHRR hypomethylation in heavy smokers: Associations with lung cancer risk and mortality

Hypomethylation of cg05575921 in the aryl-hydrocarbon receptor repressor (AHRR) gene is consistently and strongly associated with higher exposure to smoking (e.g., current smoking, greater number of pack years, and less time since quitting). Although cg05575921 hypomethylation has been reported to be associated with lung cancer risk and mortality, this has not been explored within heavy smokers or by histotype. We assessed cg05575921 methylation for associations with smoking behavior, prospective lung cancer risk, and mortality in 313 cases and controls from the Beta Carotene and Retinol Efficacy Trial (CARET) with ≥20 pack years of smoking and matched on age (±5 years), sex, race/ethnicity, enrollment year, smoking status, occupational asbestos exposure, and follow-up time. Methylation of cg05575921 in blood collected on average 4.3 years prior to diagnosis in cases was assayed using the 850K Illumina EPIC array. Quintiles of cg05575921 methylation were defined based on the control distribution, with the lowest quintile (Q1, referent) representing hypermethylation and the highest (Q5), hypomethylation. Among controls, increasing quintiles of cg05575921 hypomethylation were associated with current smoking status (Cochran-Armitage trend p=3.0 × 10-21), and with decreasing years since last smoked, increasing cigarettes per day, and decreasing body mass index (BMI) (ordinal ANOVA p=3.1 × 10-21, 1.3 × 10-17, and 0.002, respectively). We observed similar patterns in cases. We evaluated associations between cg05575921 methylation and lung cancer risk using logistic regression models conditioned on matching factors and adjusted for age, years since quit, and BMI. We evaluated cg05575921 methylation and lung cancer-specific mortality using Cox proportional hazards models adjusted for stage, age, sex, race, smoking status, intervention arm, asbestos exposure, and pack years smoked. We did not observe clear patterns of associations between cg05575921 methylation and lung cancer risk overall or by histotype. However, we found a linear relationship (p=0.03) between increasing cg05575921 hypomethylation and overall lung cancer mortality, with Q5 vs Q1 Hazard Ratio (HR)=1.60 (95% Confidence Interval (95% CI): 1.00-2.57) for mortality from lung cancer overall, and HR=2.09, 95% CI: 0.96-4.54 for adenocarcinoma (N=121). Our findings provide preliminary support that even among heavy smokers, cg05575921 hypomethylation is associated with more recent and extensive exposure to cigarette smoking, and that prediagnosis cg05575921 hypomethylation in lung cancer cases is associated with an increased hazard of death. However, since the CARET population represents a group who would largely qualify for lung cancer screening with annual low-dose computed tomography per the United States Preventive Task Force guidelines, our results do not provide support for the use of cg05575921 hypomethylation as an indicator for screening-based lung cancer risk stratification.

Citation Format: Stefan Graw, Matt J. Barnett, Mark D. Thornquist, Gary E. Goodman, Chu Chen, Devin C. Koestler, Carmen J. Marsit, Jennifer A. Doherty, Laurie Grieshober. AHRR hypomethylation in heavy smokers: Associations with lung cancer risk and mortality [abstract]. In: Proceedings of the AACR Special Conference on Modernizing Population Sciences in the Digital Age; 2019 Feb 19-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(9 Suppl):Abstract nr A20.

Abstract 3300: Pre-diagnosis neutrophil-to-lymphocyte ratio and lung cancer mortality

The neutrophil-to-lymphocyte ratio (NLR) is a marker of systemic inflammation that has been reported to be associated with smoking status as well as survival outcomes from chronic diseases including lung cancer. Most prior studies have examined NLR measured in blood collected at diagnosis, which may therefore reflect disease-related inflammation. Although blood cell type counts, and therefore NLR, cannot be quantified in stored samples, algorithms have been developed to estimate blood cell type counts based on lineage-specific DNA methylation patterns across the genome as methylation-derived NLR (mdNLR). We hypothesize that the inflammatory profile reflected by pre-diagnosis mdNLR may be associated with lung cancer mortality. To test this hypothesis, we examined mdNLR and lung cancer-specific mortality, overall and by histotype, among 293 cases from the Beta Carotene and Retinol Efficacy Trial (CARET) of heavy smokers (≥20 pack years). We used the ratio of predicted neutrophil and lymphocyte proportions derived from DNA methylation signatures in whole blood samples collected on average 4.1 years prior to diagnosis, to estimate mdNLR, which was discretized as quartiles ranging from lowest to highest; i.e. low to high levels of systemic inflammation. We fit Cox proportional hazards models adjusted for age, sex, race (white vs non-white), smoking status, intervention arm, asbestos exposure, and pack years smoked to examine the association between mdNLR lung cancer-specific mortality. We also adjusted for time between blood draw and diagnosis and included early versus late stage as a stratification variable. mdNLR was not associated with mortality for all cases combined, nor squamous cell carcinoma (N=100) or small cell lung cancer (N=59). In contrast, for adenocarcinoma (N=122), we observed a statistically significant linear trend (p=0.02) for increasing quartiles of mdNLR and adenocarcinoma-specific mortality, with a hazard ratio (HR) of 2.03 (95% Confidence Interval (CI): 1.03-4.03) comparing the highest (Q4) to lowest (Q1) mdNLR quartiles. Though subgroup analyses were sparse, we observed associations of larger magnitude (Q4 compared to Q1) for those who were younger at blood draw (HR=4.70, 95% CI: 1.73-12.76) and at diagnosis (HR=6.09, 95% CI: 1.98-18.72), as well as those with smoking histories lower than the median of 53 pack years (HR=2.91, 95% CI: 1.03-8.22) and those in the active intervention arm (HR=3.32, 95% CI: 1.11-9.93). Our findings suggest that an inflammatory response prior to diagnosis as indicated by higher mdNLR levels may be associated with mortality in heavy smokers who go on to develop lung adenocarcinoma. Since indicators of survival may be used to guide treatment decisions and gauge response to treatment, further research into the association between mdNLR and lung adenocarcinoma-specific survival is needed to understand its potential clinical utility.

Citation Format: Laurie Grieshober, Stefan Graw, Matt J. Barnett, Mark D. Thornquist, Gary E. Goodman, Chu Chen, Devin Koestler, Carmen Marsit, Jennifer Doherty. Pre-diagnosis neutrophil-to-lymphocyte ratio and lung cancer mortality [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3300.

Prediagnostic circulating markers of inflammation and risk of oesophageal adenocarcinoma: a study within the National Cancer Institute Cohort Consortium

OBJECTIVE

Cross-sectional data indicate that systemic inflammation is important in oesophageal adenocarcinoma. We conducted a prospective study to assess whether prediagnostic circulating markers of inflammation were associated with oesophageal adenocarcinoma and to what extent they mediated associations of obesity and cigarette smoking with cancer risk.

DESIGN

This nested case-control study included 296 oesophageal adenocarcinoma cases and 296 incidence density matched controls from seven prospective cohort studies. We quantitated 69 circulating inflammation markers using Luminex-based multiplex assays. Conditional logistic regression models estimated associations between inflammation markers and oesophageal adenocarcinoma, as well as direct and indirect effects of obesity and smoking on risk of malignancy.

RESULTS

Soluble tumour necrosis factor receptor 2 (sTNFR2) (ORsquartile 4 vs 1=2.67, 95% CI 1.52 to 4.68) was significantly associated with oesophageal adenocarcinoma. Additional markers close to the adjusted significance threshold included C reactive protein, serum amyloid A, lipocalin-2, resistin, interleukin (IL) 3, IL17A, soluble IL-6 receptor and soluble vascular endothelial growth factor receptor 3. Adjustment for body mass index, waist circumference or smoking status slightly attenuated biomarker-cancer associations. Mediation analysis indicated that sTNFR2 may account for 33% (p=0.005) of the effect of waist circumference on oesophageal adenocarcinoma risk. Resistin, plasminogen activator inhibitor 1, C reactive protein and serum amyloid A were also identified as potential mediators of obesity-oesophageal adenocarcinoma associations. For smoking status, only plasminogen activator inhibitor 1 was a nominally statistically significant (p<0.05) mediator of cancer risk.

CONCLUSION

This prospective study provides evidence of a link between systemic inflammation and oesophageal adenocarcinoma risk. In addition, this study provides the first evidence that indirect effects of excess adiposity and cigarette smoking, via systemic inflammation, increase the risk of oesophageal adenocarcinoma.

Agnostic Pathway/Gene Set Analysis of Genome-Wide Association Data Identifies Associations for Pancreatic Cancer

BACKGROUND

Genome-wide association studies (GWAS) identify associations of individual single-nucleotide polymorphisms (SNPs) with cancer risk but usually only explain a fraction of the inherited variability. Pathway analysis of genetic variants is a powerful tool to identify networks of susceptibility genes.

METHODS

We conducted a large agnostic pathway-based meta-analysis of GWAS data using the summary-based adaptive rank truncated product method to identify gene sets and pathways associated with pancreatic ductal adenocarcinoma (PDAC) in 9040 cases and 12 496 controls. We performed expression quantitative trait loci (eQTL) analysis and functional annotation of the top SNPs in genes contributing to the top associated pathways and gene sets. All statistical tests were two-sided.

RESULTS

We identified 14 pathways and gene sets associated with PDAC at a false discovery rate of less than 0.05. After Bonferroni correction (P ≤ 1.3 × 10-5), the strongest associations were detected in five pathways and gene sets, including maturity-onset diabetes of the young, regulation of beta-cell development, role of epidermal growth factor (EGF) receptor transactivation by G protein-coupled receptors in cardiac hypertrophy pathways, and the Nikolsky breast cancer chr17q11-q21 amplicon and Pujana ATM Pearson correlation coefficient (PCC) network gene sets. We identified and validated rs876493 and three correlating SNPs (PGAP3) and rs3124737 (CASP7) from the Pujana ATM PCC gene set as eQTLs in two normal derived pancreas tissue datasets.

CONCLUSION

Our agnostic pathway and gene set analysis integrated with functional annotation and eQTL analysis provides insight into genes and pathways that may be biologically relevant for risk of PDAC, including those not previously identified.

Methylation-derived Neutrophil-to-Lymphocyte Ratio and Lung Cancer Risk in Heavy Smokers

The neutrophil-to-lymphocyte ratio (NLR) is a biomarker that indicates systemic inflammation and can be estimated using array-based DNA methylation data as methylation-derived NLR (mdNLR). We assessed the relationship between prediagnosis mdNLR and lung cancer risk in a nested case-control study in the β-Carotene and Retinol Efficacy Trial (CARET) of individuals at high risk for lung cancer due to heavy smoking or substantial occupational asbestos exposure. We matched 319 incident lung cancer cases to controls based on age at blood draw, smoking, sex, race, asbestos, enrollment year, and time at risk. We computed mdNLR using the ratio of predicted granulocyte and lymphocyte proportions derived from DNA methylation signatures in whole blood collected prior to diagnosis (median 4.4 years in cases). Mean mdNLR was higher in cases than controls (2.06 vs. 1.86, P = 0.03). Conditional logistic regression models adjusted for potential confounders revealed a 21% increased risk of lung cancer per unit increase in mdNLR [OR 1.21; 95% confidence interval (CI) 1.01-1.45]. A 30% increased risk of non-small cell lung cancer (NSCLC) was observed for each unit increase in mdNLR (n = 240 pairs; OR 1.30, 95% CI, 1.03-1.63), and there was no statistically significant association between mdNLR and small-cell lung cancer risk. The mdNLR-NSCLC association was most pronounced in those with asbestos exposure (n = 42 male pairs; OR 3.39; 95% CI, 1.32-8.67). A better understanding of the role of mdNLR in lung cancer etiology may improve prevention and detection of lung cancer. Cancer Prev Res; 11(11); 727-34. ©2018 AACR.

Abstract 3235: Pre-diagnosis neutrophil-to-lymphocyte ratio and lung cancer risk in heavy smokers

The neutrophil-to-lymphocyte ratio (NLR) is a marker of systemic inflammation that is inversely associated with survival for many chronic diseases, including lung cancer. We hypothesize that the inflammatory profile reflected by DNA methylation-derived NLR (mdNLR) may also be associated with lung cancer risk. We assessed the relationship between pre-diagnosis mdNLR and lung cancer risk in a nested case-control study of the β-Carotene and Retinol Efficacy Trial (CARET), a population at high risk for lung cancer due to heavy smoking (≥20 pack years; current smoker or quit ≤6 years before enrollment) or substantial occupational asbestos exposure (current smoker or quit ≤15 years before enrollment). We matched 319 incident lung cancer cases to controls based on time at risk, age at blood draw, smoking status, sex, race, asbestos exposure, and enrollment year. We computed mdNLR using the ratio of predicted neutrophil and lymphocyte proportions derived from DNA methylation signatures in whole blood samples collected prior to diagnosis (mean 4.31 years in cases). Conditional logistic regression models were adjusted for potential confounding factors: age, pack years of smoking, cigarettes per day, and body mass index. Mean mdNLR was higher in cases at 2.06 than in controls at 1.86 (p=0.04). Each unit increase in mdNLR was associated with a 21% increased risk of lung cancer (Odds Ratio (OR) 1.21, 95% Confidence Interval (CI) 1.01-1.45). There was a 30% increased risk of non-small cell lung cancer (NSCLC; n=240 pairs; 1.30, 1.03-1.63); estimates for adenocarcinoma and squamous cell NSCLC were similar. mdNLR was not associated with small cell lung cancer (n=68 pairs; 1.06, 0.77-1.47). The association between mdNLR and NSCLC risk was most pronounced in those with asbestos exposure (3.39, 1.32-8.67; all men). Estimates for NSCLC cases without asbestos exposure were similar for men (1.15, 0.88-1.51) and women (1.22, 0.75-1.98). We assessed whether mdNLR and NSCLC risk associations varied by tertiles of time at risk among cases: 0-2.7 years, 2.8-5.4 years, and 5.5-9.8 years. Though NSCLC risk was suggestively elevated in each time period stratum, the magnitude of the association was largest for the time period closest to diagnosis (1.49, 0.92-2.41; 1.26, 0.86-1.84; and 1.30, 0.88-1.91, respectively). This is the first study to evaluate whether pre-diagnosis mdNLR is associated with lung cancer risk, and we assessed this association in a sample of heavy smokers. Our findings suggest that the inflammatory response produced by both smoking and asbestos may be reflected by mdNLR. A better understanding of the role of mdNLR in NSCLC etiology may improve detection of nascent lung cancer, thereby improving treatment strategies in NSCLC patients.

Citation Format: Laurie Grieshober, Stefan Graw, Matt J. Barnett, Mark D. Thornquist, Gary E. Goodman, Chu Chen, Devin C. Koestler, Carmen J. Marsit, Jennifer A. Doherty. Pre-diagnosis neutrophil-to-lymphocyte ratio and lung cancer risk in heavy smokers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3235.

Nested case-control study of telomere length and lung cancer risk among heavy smokers in the β-Carotene and Retinol Efficacy Trial

Background

Telomeres protect cells from genomic instability. We examined telomere length and lung cancer risk prospectively in heavy smokers.

Methods

In a nested case–control study with 709 cases and 1313 controls, conditional logistic regression was used to evaluate associations between telomere length (global, chromosome 5p, and 13q) and lung cancer risk by histotype, controlling for detailed smoking history.

Results

Risks of overall lung cancer and adenocarcinoma were suggestively elevated among individuals with telomere length in the longest tertile. No clear patterns were observed for other histotypes, or for chromosome 5p or 13q telomere length. Associations with adenocarcinoma were strongest among (OR, 95% CI for longest versus shortest tertile): former smokers (2.26, 1.03–4.96), individuals <65 years (2.22, 1.13–4.35), and women (2.21, 0.99–4.93).

Conclusions

Our large study of heavy smokers adds additional evidence that long telomere length prior to diagnosis is associated with risk of lung adenocarcinoma, but not other histotypes.

Inflammatory Gene Polymorphisms in Lung Cancer Susceptibility

INTRODUCTION

Chronic inflammation has been implicated in carcinogenesis, with increasing evidence of its role in lung cancer. We aimed to evaluate the role of genetic polymorphisms in inflammation-related genes in the risk for development of lung cancer.

METHODS

A nested case-control study design was used, and 625 cases and 625 well-matched controls were selected from participants in the β-Carotene and Retinol Efficacy Trial, which is a large, prospective lung cancer chemoprevention trial. The association between lung cancer incidence and survival and 23 polymorphisms descriptive of 11 inflammation-related genes (interferon gamma gene [IFNG], interleukin 10 gene [IL10], interleukin 1 alpha gene [IL1A], interleukin 1 beta gene [IL1B], interleukin 2 gene [IL2], interleukin 4 receptor gene [IL4R], interleukin 4 gene [IL4], interleukin 6 gene [IL6], prostaglandin-endoperoxide synthase 2 gene [PTGS2] (also known as COX2), transforming growth factor beta 1 gene [TGFB1], and tumor necrosis factor alpha gene [TNFA]) was evaluated.

RESULTS

Of the 23 polymorphisms, two were associated with risk for lung cancer. Compared with individuals with the wild-type (CC) variant, individuals carrying the minor allele variants of the IL-1β-511C>T promoter polymorphism (rs16944) (CT and TT) had decreased odds of lung cancer (OR = 0.74, [95% confidence interval (CI): 0.58-0.94] and OR = 0.71 [95% CI: 0.50-1.01], respectively, p = 0.03). Similar results were observed for the IL-1β-1464 C>G promoter polymorphism (rs1143623), with presence of the minor variants CG and CC having decreased odds of lung cancer (OR = 0.75 [95% CI: 0.59-0.95] and OR = 0.69 [95% CI: 0.46-1.03], respectively, p = 0.03). Survival was not influenced by genotype.

CONCLUSIONS

This study provides further evidence that IL1B promoter polymorphisms may modulate the risk for development of lung cancer.

Genome-wide meta-analysis identifies five new susceptibility loci for pancreatic cancer

In 2020, 146,063 deaths due to pancreatic cancer are estimated to occur in Europe and the United States combined. To identify common susceptibility alleles, we performed the largest pancreatic cancer GWAS to date, including 9040 patients and 12,496 controls of European ancestry from the Pancreatic Cancer Cohort Consortium (PanScan) and the Pancreatic Cancer Case-Control Consortium (PanC4). Here, we find significant evidence of a novel association at rs78417682 (7p12/TNS3, P = 4.35 × 10-8). Replication of 10 promising signals in up to 2737 patients and 4752 controls from the PANcreatic Disease ReseArch (PANDoRA) consortium yields new genome-wide significant loci: rs13303010 at 1p36.33 (NOC2L, P = 8.36 × 10-14), rs2941471 at 8q21.11 (HNF4G, P = 6.60 × 10-10), rs4795218 at 17q12 (HNF1B, P = 1.32 × 10-8), and rs1517037 at 18q21.32 (GRP, P = 3.28 × 10-8). rs78417682 is not statistically significantly associated with pancreatic cancer in PANDoRA. Expression quantitative trait locus analysis in three independent pancreatic data sets provides molecular support of NOC2L as a pancreatic cancer susceptibility gene.

Abstract 4958: Prediagnostic peripheral blood DNA methylation and lung cancer survival

Epigenetic regulation plays a critical role in cell and tissue development and differentiation, is a known mechanism of carcinogenesis, and is altered by various exposures including cigarette smoking and age. Peripheral blood methylation represents a combination of these factors as well as blood cell type distributions that reflect underlying immunophenotypes. Hematopoiesis is programmed through epigenetic changes, and blood cell type-specific methylation markers can be leveraged to “fingerprint” cell type distributions. We examined associations between pre-diagnostic methylation markers in peripheral blood with overall lung cancer survival in very heavy smokers from the Beta Carotene and Retinol Efficacy Trial (CARET). CARET was a randomized, double-blinded, placebo-controlled chemoprevention trial of daily β-carotene and retinyl palmitate in smokers with ≥20 pack-years, and smokers who were occupationally exposed to asbestos. Methylation was successfully measured using the Illumina 850K EPIC BeadArray on average 5 years prior to diagnosis for 331 lung cancer cases, of whom 253 died during follow up (median survival 329 days). Cox proportional hazards regression models were used to examine the relationship between CpG-specific methylation and survival. Models were adjusted for age at blood draw, sex, race, enrollment year, placebo/active intervention, asbestos exposure, current/former smoking and time since quit, pack years, average number of cigarettes per day and histologic type, and were fit separately depending on the time between blood draw and lung cancer diagnosis: 0-3 years (n = 107), 3-5 years (n = 77), and 5+ years (n = 147). After adjusting for multiple comparisons by computing the false discovery rate (FDR) q-value, there were 1,028, 296, and 4 CpGs that were statistically significantly associated with survival (q ≤0.010) for samples collected 0-3 years, 3-5 years, and 5+ years before diagnosis, respectively. After controlling for blood cell type distributions, much larger numbers of CpGs were statistically significantly associated with survival: 10,481, 456, and 257, respectively. The top canonical pathways of CpGs identified in samples drawn 0-3 years prior to diagnosis included PTEN signaling (p = 1.1E-5) and PI3K signaling in B lymphoctyes (p = 3.7E-5). We observed that the number of methylated CpGs in peripheral blood that are associated with subsequent survival increases dramatically when measured closer to lung cancer diagnosis. As well, we observed that the number of methylated markers is increased by controlling for immunophenotype. Our study provides evidence that peripheral blood methylation markers measured many years prior to diagnosis may be associated with poor lung cancer survival, and that increasing changes in methylation over time may also be associated. This points to the critical role of the immune system, even prior to diagnosis, in influencing cancer outcomes.

Citation Format: Jennifer A. Doherty, Xuan Zhang, Devin C. Koestler, Matt J. Barnett, Mark D. Thornquist, Gary E. Goodman, Carmen J. Marsit. Prediagnostic peripheral blood DNA methylation and lung cancer survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4958. doi:10.1158/1538-7445.AM2017-4958

A multiplex immunoassay for the non-invasive detection of bladder cancer

BACKGROUND

Urine based assays that can non-invasively detect bladder cancer (BCa) have the potential to reduce unnecessary and invasive procedures. The purpose of this study was to develop a multiplex immunoassay that can accurately and simultaneously monitor ten diagnostic urinary protein biomarkers for application as a non-invasive test for BCa detection.

METHODS

A custom electrochemiluminescent multiplex assay was constructed (Meso Scale Diagnostics, LLC, Rockville, MD, USA) to detect the following urinary proteins; IL8, MMP9, MMP10, ANG, APOE, SDC1, A1AT, PAI1, CA9 and VEGFA. Voided urine samples from two cohorts were collected prior to cystoscopy and samples were analyzed blinded to the clinical status of the participants. Means (±SD) and receiver operating characteristic (ROC) curve analysis were used to compare assay performance and to assess the diagnostic accuracy of the diagnostic signature.

RESULTS

Comparative diagnostic performance analyses revealed an AUROC value of 0.9258 for the multiplex assay and 0.9467 for the combination of the single-target ELISA assays (p = 0.625), so there was no loss of diagnostic utility for the MSD multiplex assay. Analysis of the independent 200-sample cohort using the multiplex assay achieved an overall diagnostic sensitivity of 0.85, specificity of 0.81, positive predictive value 0.82 and negative predictive value 0.84.

CONCLUSIONS

It is technically feasible to simultaneously monitor complex urinary diagnostic signatures in a single assay without loss of performance. The described protein-based assay has the potential to be developed for the non-invasive detection of BCa.

Abstract 4593: Telomere length measured prior to lung cancer diagnosis and survival by histologic type

Short telomere length is thought to be a marker of increased cumulative cellular aging, and has been reported to be associated with poor survival from a variety of cancer types, including lung cancer. We examined associations between telomere length and overall survival for the major lung cancer histologic types in very heavy smokers from the Beta Carotene and Retinol Trial (CARET). CARET was a randomized, double-blinded, placebo-controlled chemoprevention trial of daily β-carotene and retinyl palmitate in smokers with ≥20 pack-years, and smokers who were occupationally exposed to asbestos. Individuals who provided blood and were later diagnosed with lung cancer were included in the study. Telomere length was successfully measured on average 5 years prior to diagnosis for 711 lung cancer cases, of whom 648 died during follow up (median survival 1.5 years). Telomere length was negatively associated with increasing age (p&lt;0.0001), but was not associated with any aspect of smoking exposure. Hazard ratios (HRs) for decreasing quintiles of telomere length were calculated using Cox proportional hazards regression. After controlling for age at blood draw, sex, race, enrollment year, placebo/active intervention, asbestos exposure, current/former smoking and time since quit, pack years, average number of cigarettes per day, tumor stage and histologic type, shorter telomere length was associated with decreased survival. Overall, HRs and 95% confidence intervals (CIs) for decreasing quintiles of telomere length and risk of death were: 1.0 (reference), 1.40 (1.08-1.83), 1.21 (0.94-1.54), 1.46 (1.13-1.89), and 1.37 (1.05-1.78), p trend = 0.02. Associations were considerably stronger for small cell carcinoma (HRs (95% CIs): 1.0, 3.39 (1.45-7.94), 1.88 (0.95-3.72), 3.62 (1.68-7.81), 2.91 (1.37-6.22), p = 0.01) and adenocarcinoma (HRs (95% CIs): 1.0, 1.00 (0.57-1.78), 1.23 (0.72-2.11), 1.78 (1.02-3.10), 1.77 (1.03-3.05), p = 0.01), than for squamous cell carcinoma (HRs (95% CIs): 1.0, 2.58 (1.29-5.15), 0.97 (0.52-1.82), 1.24 (0.65-2.34), 1.17 (0.58-2.35), p = 0.99), and stronger for stage III/IV disease (HRs (95% CIs): 1.0, 1.55 (1.07-2.23), 1.21 (0.88-1.67), 1.74 (1.23-2.47), 1.48 (1.05-2.08), p = 0.02) than for early stage disease (HRs (95% CIs): 1.0, 1.05 (0.55-2.03), 0.68 (0.37-1.26), 1.11 (0.60-2.05), 1.06 (0.53-2.09), p = 0.88). As well, short telomere length was associated with particularly poor survival among individuals &lt;65 years at diagnosis (HRs (95% CIs): 1.0, 2.37 (1.35-4.15), 1.99 (1.16-3.44), 2.31 (1.21-4.40), 2.93 (1.61-5.33), p = 0.0007) but not among individuals ages 65 and older (HRs (95% CIs): 1.0, 1.15 (0.85-1.56), 0.98 (0.74-1.30), 1.26 (0.94-1.68), 1.09 (0.81-1.47), p = 0.39). Short telomere length measured prior to diagnosis may be a marker for poor survival after a diagnosis of lung cancer, particularly for small cell carcinoma and adenocarcinoma, and for individuals diagnosed before age 65.

Citation Format: Jennifer A. Doherty, John Houck, Matt J. Barnett, Jean DD Tapsoba, Liberto Julianto, Mark D. Thornquist, Ching-Yun Wang, Chu Chen, Gary E. Goodman. Telomere length measured prior to lung cancer diagnosis and survival by histologic type. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4593. doi:10.1158/1538-7445.AM2015-4593

Estimated intake of vitamin D and its interaction with vitamin A on lung cancer risk among smokers

Data are very limited on vitamin D and lung cancer prevention in high-risk populations. The authors investigated whether estimated vitamin D intake was associated with lung cancer risk and whether effect modification by vitamin A existed among current/former heavy smokers and workers with occupational exposure to asbestos. A case-cohort study selected 749 incident lung cancers and 679 noncases from the Carotene and Retinol Efficacy Trial (CARET), 1988-2005. The active intervention was supplementation of 30 mg β-carotene + 25,000 IU retinyl palmitate/day. Baseline total intake including both diet (from food frequency questionnaire) and personal supplements (from brand names linked to the labeled potencies) was assessed. Hazard ratios (HRs) were estimated by Cox proportional hazard models. No significant association of total vitamin D intake with lung cancer was observed overall. However, total vitamin D intake ≥600 versus <200 IU/day was associated with a lower risk of non-small cell lung cancer among former smokers [HR = 0.36, 95% confidence interval (CI) = 0.13-0.96]. Total vitamin D intake ≥400 versus <400 IU/day was associated with a lower risk of total lung cancer among participants who received the CARET active intervention (HR = 0.56, 95% CI = 0.32-0.99) and among those who had total vitamin A intake ≥1,500 µg/day retinol activity equivalent (RAE; HR = 0.46, 95% CI = 0.23-0.91). The beneficial associations were attenuated among those who did not receive the CARET active intervention or who had total vitamin A intake <1,500 µg/day RAE (p-interaction = 0.02 for current smokers). Our observation suggests that vitamin A may assist vitamin D in preventing lung cancer among smokers.

No evidence of gene-calcium interactions from genome-wide analysis of colorectal cancer risk

BACKGROUND

Calcium intake may reduce risk of colorectal cancer, but the mechanisms remain unclear. Studies of interaction between calcium intake and SNPs in calcium-related pathways have yielded inconsistent results.

METHODS

To identify gene-calcium interactions, we tested interactions between approximately 2.7 million SNPs across the genome with self-reported calcium intake (from dietary or supplemental sources) in 9,006 colorectal cancer cases and 9,503 controls of European ancestry. To test for multiplicative interactions, we used multivariable logistic regression and defined statistical significance using the conventional genome-wide α = 5E-08.

RESULTS

After accounting for multiple comparisons, there were no statistically significant SNP interactions with total, dietary, or supplemental calcium intake.

CONCLUSIONS

We found no evidence of SNP interactions with calcium intake for colorectal cancer risk in a large population of 18,509 individuals.

IMPACT

These results suggest that in genome-wide analysis common genetic variants do not strongly modify the association between calcium intake and colorectal cancer in European populations.

Vitamin D intake determines vitamin d status of postmenopausal women, particularly those with limited sun exposure

Few detailed data are available on the wide range of determinants of vitamin D status among postmenopausal women, and it is also unclear whether there may be undiscovered determinants. The objective of this study was to comprehensively evaluate determinants of serum 25-hydroxyvitamin D [25(OH)D] concentrations in a large cohort of postmenopausal women. Data from a subset of the Women's Health Initiative Observational Study were analyzed (50-79 y; n = 3345). Information on diet, lifestyle behaviors, secondhand smoke, use of dietary supplements and medication, chronic diseases, and anthropometry was collected at baseline (1993-1998) and on sun exposure at year 4 follow-up. Linear regression was performed to estimate regression coefficients (β). Significant determinants were total vitamin D intake (food plus supplements per 100 IU/d, β = 2.08), years of supplemental vitamin D use (β = 0.15), total fat intake (grams per day, β = -0.03), smoking status (β = -2.64, current vs. never), regional solar irradiance (β = 6.26, 475-500 vs. 300-325 Langleys), daylight time spent outdoors in summer (β = 5.15, >2 h vs. <30 min/d), recreational physical activity (metabolic equivalent task per hour per week, β = 0.13), waist circumference (centimeters, β = -0.26), and race/ethnicity (β = -11.94, black vs. white). Total vitamin D intake (partial R(2) = 0.09) explained the most variance in serum 25(OH)D concentrations (total R(2) = 0.29). The association between total vitamin D intake and serum 25(OH)D concentrations was stronger among participants who spent less rather than more daylight time outdoors in summer (P-interaction = 0.026). History and medications for hypertension, hyperlipidemia, and type 2 diabetes and secondhand smoke exposure were not associated with serum 25(OH)D. In conclusion, dietary factors and sun exposure remain important determinants of vitamin D status in postmenopausal women. Vitamin D intake should be emphasized for those with limited sun exposure.

Vitamin D intake and lung cancer risk in the Women's Health Initiative

BACKGROUND

Prior research suggests that vitamin D protects against lung cancer only among certain subgroups.

OBJECTIVES

We investigated whether vitamin D intake was associated with lung cancer and explored whether vitamin A intake modified the association.

DESIGN

Prospective cohort data from 128,779 postmenopausal women, including 1771 incident lung cancers in the Women's Health Initiative (Clinical Trials and Observational Study) 1993-2010, were analyzed. Twelve percent of women received active intervention (1 g Ca + 400 IU vitamin D3/d) in the Calcium/Vitamin D Trial. Baseline total intake included both dietary intake (from food-frequency questionnaires) and supplement intake (from bottle labels). HRs were estimated by Cox proportional hazard models.

RESULTS

No significant association was observed overall. Among never smokers, a total vitamin D intake ≥400 IU/d was significantly associated with lower risks of lung cancer (HR: 0.37; 95% CI: 0.18, 0.77 for ≥800 compared with <100 IU/d; P-trend = 0.01). No significant effect modification of total vitamin A intake on the association between total vitamin D intake and lung cancer was found. However, the Calcium/Vitamin D Trial active intervention was significantly associated with a lower lung cancer risk only among women with a vitamin A intake <1000 μg/d retinol activity equivalents (HR: 0.69; 95% CI: 0.50, 0.96; P-interaction = 0.09).

CONCLUSIONS

Vitamin D intake was associated with a lower lung cancer risk in never-smoking, postmenopausal women. Lower vitamin A intake may be important for a beneficial association of 1 g Ca + 400 IU vitamin D3 supplementation with lung cancer. This trial was registered at clinicaltrials.gov as NCT00000611.

Serum phospholipid fatty acids, genetic variation in myeloperoxidase, and prostate cancer risk in heavy smokers: a gene-nutrient interaction in the carotene and retinol efficacy trial

The authors investigated associations of serum phospholipid n-3 and n-6 polyunsaturated fatty acids (PUFAs) and trans-fatty acids with prostate cancer risk, and whether myeloperoxidase G-463A (rs2333227) modified the associations in the Carotene and Retinol Efficacy Trial (CARET) (Seattle, Washington; Irvine, California; New Haven, Connecticut; San Francisco, California; Baltimore, Maryland; and Portland, Oregon, 1985-2003). Prerandomization sera were assayed for fatty acids among 641 men with incident prostate cancer (368 nonaggressive and 273 aggressive (stage III/IV or Gleason score ≥7)) and 1,398 controls. Overall, dihomo-γ-linolenic (quartiles 4 vs. 1: odds ratio (OR) = 0.66, 95% confidence interval (CI): 0.49, 0.95; P(trend) = 0.024) and docosatetraenoic (OR = 0.69, 95% CI: 0.46, 1.02; P(trend) = 0.011) acids were inversely associated with nonaggressive and aggressive prostate cancer risks, respectively. Among men with MPO GG, the genotype upregulating oxidative stress, quartiles 4 versus 1 eicosapentaenoic plus docosahexaenoic acids were suggestively associated with an increased risk of aggressive prostate cancer (OR = 1.66, 95% CI: 0.95, 2.92; P(trend) = 0.07). However, the association was the inverse among men with MPO GA/AA genotypes (P(interaction) = 0.011). Interactions were also observed for docosapentaenoic acid, total n-3 PUFAs, and arachidonic acid. MPO GA/AA vs. GG was associated with a 2-fold increase in aggressive prostate cancer risk among men with low (quartile 1) n-3 PUFAs. This study adds important evidence linking oxidative stress with prostate carcinogenesis.

Abstract 2572: Vitamin D intake and lung cancer risk in the Women's Health Initiative (WHI)

Background: Prior research suggests that vitamin D protects against lung cancer with evidence only among subgroups including women and non-smokers. We investigated whether vitamin D intake was associated with lung cancer and explored whether vitamin A intake modified the association.

Methods: Data from 128,779 postmenopausal women including 1,771 incident lung cancers in the Women's Health Initiative, 1993-2010, were analyzed. Twelve percent of women received active intervention (1 g calcium+400 IU vitamin D3 daily) in the Calcium/Vitamin D Trial. Baseline total intake was assessed by a food frequency questionnaire and supplement bottle labels. Hazard ratios (HR) were estimated by Cox proportional hazard models.

Results: No association was observed overall. Among never smokers, vitamin D intake was inversely associated with total lung cancer (HR=0.37, 95% confidence interval [CI]=0.18-0.77, ≥800 vs. &lt;100 IU/d; P-trend=0.01). The Calcium/Vitamin D Trial active intervention was not associated with a lower lung cancer risk among women with vitamin A intake ≥1,000 μg/d Retinol Activity Equivalent (RAE), but among those with vitamin A intake &lt;1,000 μg/d RAE (HR=0.69, 95% CI=0.50-0.96; P-interaction=0.09). Among current smokers with excess vitamin A intake (≥3,000 μg/d RAE), the intervention was associated with a higher lung cancer risk (HR=2.26, 95% CI=1.02-5.01), as no association was observed among current smokers with vitamin A intake &lt;3,000 μg/d RAE (P-interaction=0.01).

Conclusion: Vitamin D intake was associated with a lower lung cancer risk in never-smoking, postmenopausal women. Lower vitamin A intake may be important for a beneficial association of 1 g calcium+400 IU vitamin D3 supplementation with lung cancer.

Citation Format: Ting-Yuan David Cheng, Andrea Z. LaCroix, Shirley A.A. Beresford, Gary E. Goodman, Mark D. Thornquist, Yingye Zheng, Rowan T. Chlebowski, Gloria Y.F. Ho, Marian L. Neuhouser. Vitamin D intake and lung cancer risk in the Women's Health Initiative (WHI). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2572. doi:10.1158/1538-7445.AM2013-2572

DNA repair genotype and lung cancer risk in the beta-carotene and retinol efficacy trial

Many carcinogens in tobacco smoke cause DNA damage, and some of that damage can be mitigated by the actions of DNA repair enzymes. In a case-control study nested within the Beta-Carotene and Retinol Efficacy Trial, a randomized chemoprevention trial in current and former heavy smokers, we examined whether lung cancer risk was associated with variation in 26 base excision repair, mismatch repair, and homologous recombination repair genes. Analyses were limited to Caucasians (744 cases, 1477 controls), and logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for individual SNPs and common haplotypes, with adjustment for matching factors. Lung cancer associations were observed (p<0.05) with SNPs in MSH5 (rs3131379, rs707938), MSH2 (rs2303428), UNG (rs246079), and PCNA (rs25406). MSH5 rs3131379 is a documented lung cancer susceptibility locus in complete linkage disequilibrium with rs3117582 in BAT3, and we observed associations similar in magnitude to those in prior studies (per A allele OR 1.37, 95% CI 1.13-1.65). UNG was associated with lung cancer risk at the gene level (p=0.02), and the A allele of rs246079 was associated with an increased risk (per A allele OR 1.15, 95% CI1.01-1.31). We observed stronger associations with UNG rs246079 among individuals who carried the risk genotypes (AG/AA) for MSH5 rs3131379 (pinteraction= 0.038). Our results provide additional evidence to suggest that the MSH5/BAT3 locus is associated with increased lung cancer risk among smokers, and that associations with other SNPs may vary depending upon MSH5/BAT3 genotype. Future studies to examine this possibility are warranted.

Fibulin-3 as a blood and effusion biomarker for pleural mesothelioma

BACKGROUND

New biomarkers are needed to detect pleural mesothelioma at an earlier stage and to individualize treatment strategies. We investigated whether fibulin-3 in plasma and pleural effusions could meet sensitivity and specificity criteria for a robust biomarker.

METHODS

We measured fibulin-3 levels in plasma (from 92 patients with mesothelioma, 136 asbestos-exposed persons without cancer, 93 patients with effusions not due to mesothelioma, and 43 healthy controls), effusions (from 74 patients with mesothelioma, 39 with benign effusions, and 54 with malignant effusions not due to mesothelioma), or both. A blinded validation was subsequently performed. Tumor tissue was examined for fibulin-3 by immunohistochemical analysis, and levels of fibulin-3 in plasma and effusions were measured with an enzyme-linked immunosorbent assay.

RESULTS

Plasma fibulin-3 levels did not vary according to age, sex, duration of asbestos exposure, or degree of radiographic changes and were significantly higher in patients with pleural mesothelioma (105±7 ng per milliliter in the Detroit cohort and 113±8 ng per milliliter in the New York cohort) than in asbestos-exposed persons without mesothelioma (14±1 ng per milliliter and 24±1 ng per milliliter, respectively; P<0.001). Effusion fibulin-3 levels were significantly higher in patients with pleural mesothelioma (694±37 ng per milliliter in the Detroit cohort and 636±92 ng per milliliter in the New York cohort) than in patients with effusions not due to mesothelioma (212±25 and 151±23 ng per milliliter, respectively; P<0.001). Fibulin-3 preferentially stained tumor cells in 26 of 26 samples. In an overall comparison of patients with and those without mesothelioma, the receiver-operating-characteristic curve for plasma fibulin-3 levels had a sensitivity of 96.7% and a specificity of 95.5% at a cutoff value of 52.8 ng of fibulin-3 per milliliter. In a comparison of patients with early-stage mesothelioma with asbestos-exposed persons, the sensitivity was 100% and the specificity was 94.1% at a cutoff value of 46.0 ng of fibulin-3 per milliliter. Blinded validation revealed an area under the curve of 0.87 for plasma specimens from 96 asbestos-exposed persons as compared with 48 patients with mesothelioma.

CONCLUSIONS

Plasma fibulin-3 levels can distinguish healthy persons with exposure to asbestos from patients with mesothelioma. In conjunction with effusion fibulin-3 levels, plasma fibulin-3 levels can further differentiate mesothelioma effusions from other malignant and benign effusions. (Funded by the Early Detection Research Network, National Institutes of Health, and others.).

Germ line variation in nucleotide excision repair genes and lung cancer risk in smokers

Since nucleotide excision repair (NER) is primarily responsible for detecting and removing bulky DNA lesions induced by tobacco smoke in the respiratory tract, single nucleotide polymorphisms (SNPs) in NER protein-encoding genes may influence lung cancer risk, particularly in smokers. Studies testing this hypothesis have produced inconsistent results, with most analyzing a few SNPs in relatively small population samples. In a study nested in the Beta- Carotene and Retinol Efficacy Trial, we examined 79 tag and previously reported risk-associated SNPs in the ERCC1, ERCC2, ERCC3, ERCC4, ERCC5, LIG1, POLE, XPA, and XPC genes in 744 lung cancer cases and 1,477 controls, all of whom were non-Hispanic white smokers. Using logistic regression, odds ratios (OR) and 95% confidence intervals (95% CI) were calculated to estimate lung cancer risk associated with SNP genotypes and haplotypes, adjusting for case-control matching factors. Lung cancer risk was modestly associated with LIG1 rs156640 (OR per G allele, 1.23; 95% CI, 1.08-1.40), rs156641 (OR per A allele, 1.23; 95% CI, 1.08-1.40), and rs8100261 (OR per A allele, 0.83; 95% CI, 0.76-0.98); XPA rs3176658 (OR per A allele, 0.83; 95% CI, 0.69-1.00); and ERCC2 rs50871 (OR per C allele, 1.15; 95% CI: 1.01-1.30). Associations with LIG1 and XPA, but not ERCC2, haplotypes were found. The results of this study and others suggest that inherited variants in LIG1 and possibly other NER genes may predispose to smoking-related lung cancer. Given that chance likely accounts for one or more of the associations observed, replication of our findings is needed.

Genetic variation in myeloperoxidase modifies the association of serum α-tocopherol with aggressive prostate cancer among current smokers

We investigated associations of serum α- and γ-tocopherols and their effect modification by polymorphisms in oxidative stress regulatory enzymes in relation to prostate cancer risk. In a nested case-control study in the Carotene and Retinol Efficacy Trial, prerandomized serum α- and γ-tocopherol were assayed among 684 men with incident prostate cancer [375 nonaggressive and 284 aggressive cancer (stage III/IV or Gleason score ≥7)] and 1441 controls. Manganese superoxide dismutase Ala-16Val (rs4880), glutathione peroxidase 1 Pro200Leu (rs1050450), catalase -262 C > T (rs1001179), and myeloperoxidase (MPO) G-463A (rs2333227) were genotyped. A multivariate-adjusted inverse association of serum α-tocopherol with total prostate cancer risk was observed in current smokers (OR = 0.62, 95% CI = 0.40-0.96, 4th vs. 1st quartiles). High (≥median) compared to low serum concentrations of α- and γ-tocopherol were inversely associated with aggressive prostate cancer in current smokers (OR = 0.50, 95% CI = 0.32-0.78 and OR = 0.64, 95% CI = 0.43-0.95, respectively). The association was stronger among those with MPO G/A+A/A genotypes. Among current smokers with low serum α-tocopherol concentrations, MPO G/A+A/A, the genotypes downregulating oxidative stress, were associated with an increased risk for aggressive prostate cancer (OR = 2.06, 95% CI = 1.22-3.46). Conversely, current smokers with these genotypes who had high α-tocopherol concentrations had a reduced risk for aggressive prostate cancer (OR = 0.34, 95% CI = 0.15-0.80; P-interaction = 0.001). In conclusion, among current smokers, both high serum α- and γ-tocopherol concentrations were associated with reduced risks of aggressive prostate cancer. The α-tocopherol-associated risks are modified by polymorphism in MPO G-463A.

Ovarian cancer biomarker performance in prostate, lung, colorectal, and ovarian cancer screening trial specimens

Establishing a cancer screening biomarker's intended performance requires "phase III" specimens obtained in asymptomatic individuals before clinical diagnosis rather than "phase II" specimens obtained from symptomatic individuals at diagnosis. We used specimens from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial to evaluate ovarian cancer biomarkers previously assessed in phase II sets. Phase II specimens from 180 ovarian cancer cases and 660 benign disease or general population controls were assembled from four Early Detection Research Network or Ovarian Cancer Specialized Program of Research Excellence sites and used to rank 49 biomarkers. Thirty-five markers, including 6 additional markers from a fifth site, were then evaluated in PLCO proximate specimens from 118 women with ovarian cancer and 474 matched controls. Top markers in phase II specimens included CA125, HE4, transthyretin, CA15.3, and CA72.4 with sensitivity at 95% specificity ranging from 0.73 to 0.40. Except for transthyretin, these markers had similar or better sensitivity when moving to phase III specimens that had been drawn within 6 months of the clinical diagnosis. Performance of all markers declined in phase III specimens more remote than 6 months from diagnosis. Despite many promising new markers for ovarian cancer, CA125 remains the single-best biomarker in the phase II and phase III specimens tested in this study.

Abstract 886: Germline variation in nucleotide excision repair genes and lung cancer risk in smokers

Nucleotide excision repair (NER) is the primary mechanism for detecting and repairing bulky DNA lesions, which in the respiratory tract can be induced by tobacco smoke and other environmental exposures. By altering DNA repair capacity, single nucleotide polymorphisms (SNPs) in NER protein-encoding genes may affect lung cancer risk, especially in smokers. Although meta-analyses have suggested some associations between NER SNPs and lung cancer (e.g., ERCC2 rs13181 and XPA rs1800975), they are largely built upon studies that have examined a limited number of SNPs in a few genes in fairly small samples. To comprehensively assess the influence of NER gene variation on lung cancer risk, we genotyped 78 SNPs tagging the regions spanning ±2500 base pairs of the ERCC1, ERCC2, ERCC3, ERCC4, ERCC5, LIG1, POLE, XPA and XPC genes in lung cancer cases and controls selected from the Beta-Carotene and Retinol Efficacy Trial, a randomized chemoprevention trial in smokers. Controls were matched to cases on age, sex, race, enrollment year, and baseline measures of smoking status and occupational asbestos exposure. Gene coverage by the tag SNPs selected using HapMap CEU data (dbSNP build 129, ≫5% minor allele frequency, pairwise r2 &gt;0.8) ranged from 91.7% to 100%. To assess SNP-level associations, we computed odds ratios (OR) and 95% confidence intervals (CI) adjusted for matching variables using logistic regression. To assess gene-level associations, we computed global p-values for likelihood ratio tests comparing each model with all SNPs in a given gene to that with no SNPs. Analyses were limited to Caucasians (746 cases, 1477 controls). At the gene level, XPA (pglobal=0.008) and LIG1 (pglobal=0.039) were associated with lung cancer risk. Associations were detected for two of the nine XPA SNPs examined, rs3176683 (OR per G allele: 0.77, 95% CI: 0.58-1.00, p=0.05) and rs3176658 (OR per A allele: 0.83, 95% CI: 0.69-1.00, p=0.05), and three of the eleven LIG1 SNPs examined, rs156640 (OR per G allele: 1.2, 95% CI: 1.1-1.4, p=0.002), rs156641 (OR per A allele: 1.2, 95% CI: 1.1-1.4, p=0.003), and rs8100261 (OR per A allele: 0.87, 95% CI: 0.77-0.99, p=0.03). The two XPA SNPs (r2=0.01) exhibited stronger associations when included together in a single regression model. In diplotype analyses, lung cancer risk was lower for those carrying the homozygous major genotypes of rs3176683 and rs3176658, relative to both heterozygous genotypes (OR: 0.38, 95% CI: 0.17-0.87). Lung cancer risk was higher for those carrying the homozygous minor genotypes of rs156640 and rs156641 and homozygous major genotype of rs8100261, relative to the homozygous major genotypes of rs156640 and 156641 and homozygous minor genotype of rs8100261 (OR: 1.7, 95% CI: 1.2-2.3). Although reported ERCC2 rs13181 and XPA rs1800975 associations could not be confirmed, our data nonetheless support the hypothesis that germline variation in NER genes influences lung cancer risk.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 886. doi:10.1158/1538-7445.AM2011-886

Pentraxin-3 is a novel biomarker of lung carcinoma

PURPOSE

Our objective was to validate the performance of three new candidate lung cancer biomarkers, pentraxin-3 (PTX3), human kallikrein 11 (KLK11), and progranulin.

EXPERIMENTAL DESIGN

We analyzed by commercial ELISA, and with a blinded protocol, 422 samples from 203 patients with lung carcinoma, 180 individuals with high risk for lung cancer (heavy smokers), and 43 individuals with cancers other than lung. All samples were obtained from the Early Detection Research Network (Reference set A).

RESULTS

We found that progranulin and KLK11 were not informative lung cancer biomarkers, with areas under the receiver operating characteristic curve (AUC; ROC), close to 0.50. However, PTX3 was an informative lung cancer biomarker, with considerable ability to separate lung cancer patients from high-risk controls. At 90% and 80% specificity, the sensitivities versus the high-risk control group were 37% and 48%, respectively. The discriminatory ability of PTX3 was about the same with all major subtypes and histotypes of lung cancer. The AUC of the ROC curves increased according to the disease stage, from 0.64 (stage I) to 0.72 (stage IV).

CONCLUSION

PTX3, but not KLK11 or progranulin, is a new serum biomarker for lung carcinoma. Its diagnostic sensitivity and specificity is similar to other clinically used lung cancer biomarkers. More studies are needed to establish if PTX3 has clinical utility for lung cancer diagnosis and management.

Assessing lead time of selected ovarian cancer biomarkers: a nested case-control study

Background

CA125, human epididymis protein 4 (HE4), mesothelin, B7-H4, decoy receptor 3 (DcR3), and spondin-2 have been identified as potential ovarian cancer biomarkers. Except for CA125, their behavior in the prediagnostic period has not been evaluated.

Methods

Immunoassays were used to determine concentrations of CA125, HE4, mesothelin, B7-H4, DcR3, and spondin-2 proteins in prediagnostic serum specimens (1–11 samples per participant) that were contributed 0–18 years before ovarian cancer diagnosis from 34 patients with ovarian cancer (15 with advanced-stage serous carcinoma) and during a comparable time interval before the reference date from 70 matched control subjects who were participating in the Carotene and Retinol Efficacy Trial. Lowess curves were fit to biomarker levels in cancer patients and control subjects separately to summarize mean levels over time. Receiver operating characteristic curves were plotted, and area-under-the curve (AUC) statistics were computed to summarize the discrimination ability of these biomarkers by time before diagnosis.

Results

Smoothed mean concentrations of CA125, HE4, and mesothelin (but not of B7-H4, DcR3, and spondin-2) began to increase (visually) in cancer patients relative to control subjects approximately 3 years before diagnosis but reached detectable elevations only within the final year before diagnosis. In descriptive receiver operating characteristic analyses, the discriminatory power of these biomarkers was limited (AUC statistics range = 0.56–0.75) but showed increasing accuracy with time approaching diagnosis (eg, AUC statistics for CA125 were 0.57, 0.68, and 0.74 for ≥4, 2–4, and <2 years before diagnosis, respectively).

Conclusion

Serum concentrations of CA125, HE4, and mesothelin may provide evidence of ovarian cancer 3 years before clinical diagnosis, but the likely lead time associated with these markers appears to be less than 1 year.

Occurrence of autoantibodies to annexin I, 14-3-3 theta and LAMR1 in prediagnostic lung cancer sera

PURPOSE

We have implemented a high throughput platform for quantitative analysis of serum autoantibodies, which we have applied to lung cancer for discovery of novel antigens and for validation in prediagnostic sera of autoantibodies to antigens previously defined based on analysis of sera collected at the time of diagnosis.

MATERIALS AND METHODS

Proteins from human lung adenocarcinoma cell line A549 lysates were subjected to extensive fractionation. The resulting 1,824 fractions were spotted in duplicate on nitrocellulose-coated slides. The microarrays produced were used in a blinded validation study to determine whether annexin I, PGP9.5, and 14-3-3 theta antigens previously found to be targets of autoantibodies in newly diagnosed patients with lung cancer are associated with autoantibodies in sera collected at the presymptomatic stage and to determine whether additional antigens may be identified in prediagnostic sera. Individual sera collected from 85 patients within 1 year before a diagnosis of lung cancer and 85 matched controls from the Carotene and Retinol Efficacy Trial (CARET) cohort were hybridized to individual microarrays.

RESULTS

We present evidence for the occurrence in lung cancer sera of autoantibodies to annexin I, 14-3-3 theta, and a novel lung cancer antigen, LAMR1, which precede onset of symptoms and diagnosis.

CONCLUSION

Our findings suggest potential utility of an approach to diagnosis of lung cancer before onset of symptoms that includes screening for autoantibodies to defined antigens.

The collaboration readiness of transdisciplinary research teams and centers findings from the National Cancer Institute's TREC Year-One evaluation study

Growing interest in promoting cross-disciplinary collaboration among health scientists has prompted several federal agencies, including the NIH, to establish large, multicenter initiatives intended to foster collaborative research and training. In order to assess whether these initiatives are effective in promoting scientific collaboration that ultimately results in public health improvements, it is necessary to develop new strategies for evaluating research processes and products as well as the longer-term societal outcomes associated with these programs. Ideally, evaluative measures should be administered over the entire course of large initiatives, including their near-term and later phases. The present study focuses on the development of new tools for assessing the readiness for collaboration among health scientists at the outset (during the first year) of their participation in the National Cancer Institute's Transdisciplinary Research on Energetics and Cancer (TREC) initiative. Indexes of collaborative readiness, along with additional measures of near-term collaborative processes, were administered as part of the TREC Year-One evaluation survey. Additionally, early progress toward scientific collaboration and integration was assessed, using a protocol for evaluating written research products. Results from the Year-One survey and the ratings of written products provide evidence of cross-disciplinary collaboration among participants during the first year of the initiative, and also reveal opportunities for enhancing collaborative processes and outcomes during subsequent phases of the project. The implications of these findings for future evaluations of team science initiatives are discussed.

Iron intake, oxidative stress-related genes (MnSOD and MPO) and prostate cancer risk in CARET cohort

Iron overload may increase prostate cancer risk through stimulation of oxidative stress, and endogenous pro- and antioxidant capabilities, i.e. manganese superoxide dismutase (MnSOD) and myeloperoxidase (MPO), may modify these associations. We investigated this hypothesis in the Carotene and Retinol Efficacy Trial cohort in a nested case-control study. Although there was no association between iron intake and risk overall, there was a suggestion of increased risk of clinically aggressive prostate cancer with higher iron intake [odds ratio (OR) = 1.4, 95% confidence interval (CI) = 0.9-2.0]. Associations were most notable for men with aggressive prostate cancer who were below the median consumption of total fruits and vegetables (OR = 1.8, 95% CI = 1.1-3.2). Associations between MPO -463 G to A genotype (rs2333227) and prostate cancer risk were only noted among men with aggressive cancer, with more than a 2-fold risk reduction among men with AA genotypes (OR = 0.4, 95% CI = 0.2-1.0); MnSOD was not associated with risk overall, but the MnSOD T to C (Val-9Ala, rs4880) polymorphism modified associations between risk of clinically aggressive prostate cancer and dietary iron intake (P for interaction = 0.02). Among aggressive cancer cases with the TT genotype, higher iron intake level was associated with >2-fold increase in risk (OR = 2.3, 95% CI = 1.0-4.9), whereas there was no association among men with CC genotypes (OR = 0.9, 95% CI = 0.4-2.3). Although interactions were not significant, there were similar patterns for MPO genotype, iron intake and risk. These findings suggest that higher iron intake may be associated with risk of clinically aggressive prostate cancer, and that endogenous antioxidant capabilities may modify these associations.

Olestra is associated with slight reductions in serum carotenoids but does not markedly influence serum fat-soluble vitamin concentrations

BACKGROUND

The 1996 Food and Drug Administration approval of the fat substitute olestra (sucrose polyester) called for active postmarketing surveillance because preapproval studies showed that olestra may lower circulating concentrations of fat-soluble nutrients such as vitamins and carotenoids.

OBJECTIVE

The objective of the Olestra Post-Marketing Surveillance Study was to examine whether customary consumption of olestra-containing savory snacks was associated with changes in serum fat-soluble vitamin and carotenoid concentrations among free-living persons in geographically and ethnically distinct US cities.

DESIGN

Adults (n = 2535) and their children aged 12-17 y (n = 272) in Baltimore, Minneapolis, and San Diego attended clinic visits during which data were collected on diet, savory snack consumption, lifestyle, and anthropometric indexes. Blood samples were drawn to assay carotenoids and vitamins A, D, E, and K. Data and blood samples were collected both before and after the nationwide introduction of olestra. General estimating equations were used in multivariate-adjusted models that examined olestra's association with the specified serum nutrients.

RESULTS

Compared with no intake, the top 2 tertiles of olestra use in adults were associated with circulating carotenoid concentrations that were modestly but significantly lower (4.3% to 22.4%). There were no significant associations of olestra with any serum nutrients among adolescents.

CONCLUSIONS

This active postmarketing surveillance study of a food additive suggests that small decreases in serum fat-soluble nutrients are attributable to olestra use. Although health outcomes were not measured here, it is unlikely that these small changes in nutrient measures would adversely affect health.

Evidence for excess colorectal cancer incidence among asbestos-exposed men in the Beta-Carotene and Retinol Efficacy Trial

The relation between asbestos exposure and colorectal cancer remains controversial. The authors of this 1984-2004 US study examined the association among 3,897 occupationally exposed participants in the Beta-Carotene and Retinol Efficacy Trial (CARET) for chemoprevention of lung cancer, followed prospectively for 10-18 years. When a Cox stratified proportional hazards model was used, risks of colorectal cancer were elevated among male heavy smokers exposed to asbestos. Their relative risk was 1.36 (95% confidence interval: 0.96, 1.93) when compared with that for CARET heavy smokers not exposed to asbestos, after adjusting for age, smoking history, and intervention arm. The presence of asbestos-induced pleural plaques at baseline was associated with a relative risk of 1.54 (95% confidence interval: 0.99, 2.40); colorectal cancer risk also increased with worsening pulmonary asbestosis (p = 0.03 for trend). A dose-response trend based on years of asbestos exposure was less evident. Nonetheless, these data suggest that colorectal cancer risk is elevated among men occupationally exposed to asbestos, especially those with evidence of nonmalignant asbestos-associated radiographic changes.

Prior lung disease and risk of lung cancer in a large prospective study

OBJECTIVES

While 75-90% of people who develop lung cancer are smokers, only a small proportion of smokers develop lung cancer. Identifying factors that increase a smoker's risk of developing lung cancer may help scientists to better understand the etiology of lung cancer and more effectively target high-risk groups for screening.

METHODS

Information on physician-diagnosed non-malignant lung diseases [asbestosis, asthma, chronic bronchitis or emphysema (CB/E), pneumonia, and tuberculosis] was obtained at baseline from 17,698 men and women involved in CARET, a randomized lung cancer prevention trial of beta-carotene and vitamin A among heavy smokers and asbestos-exposed workers. Hazard ratios for lung cancer were estimated through Cox regression models, after controlling for potential confounding factors, included smoking. Analyses were restricted to former and current smokers.

RESULTS

During a median follow up of 9.1 years, 1028 cases of lung cancer occurred. Those who developed lung cancer were more likely to report a history of CB/E than controls (adjusted HR = 1.29, 95% CI: 1.09-1.53). In subgroup analyses, the association between a history of CB/E and lung cancer was stronger for those who were younger at diagnosis/reference, men in the heavy smoker cohort, former smokers, and those with squamous cell carcinomas. There was little association between a history of other lung diseases and lung cancer.

CONCLUSIONS

Smokers with a history of CB/E may be at higher risk of developing lung cancer, independent of their smoking history.

Predictors of lung cancer among asbestos-exposed men in the {beta}-carotene and retinol efficacy trial

Despite numerous published studies, debate continues regarding the risk of developing lung cancer among men exposed occupationally to asbestos, particularly those without radiographic or functional evidence of asbestosis. The beta-Carotene and Retinol Efficacy Trial (CARET), a study of vitamin supplementation for chemoprevention of lung cancer, has followed 4,060 heavily exposed US men for 9-17 years. Lung cancer incidence for 1989-2002 was analyzed using a stratified proportional hazards model. The study confirmed excessive rates of lung cancer among men with radiographic asbestosis. Comparison of study arms revealed a strong, unanticipated synergy between radiographic profusion category and the active intervention. In the large subgroup of men with normal lung parenchyma on chest radiograph at baseline, there was evidence of exposure-related lung cancer risk: Men with more than 40 years' exposure in high-risk trades had a risk approximately fivefold higher than men with 5-10 years, after adjustment for covariates. The effect in these men was independent of study intervention arm, but pleural plaques on the baseline radiograph and abnormal baseline flow rate were strong independent predictors of subsequent lung cancer. Residual confounding by subclinical asbestosis, exposure to unmeasured lung carcinogens, or differences in smoking are unlikely to explain these observations better than a carcinogenic effect of asbestos per se.

Interlaboratory reliability of microimmunofluorescence test for measurement of Chlamydia pneumoniae-specific immunoglobulin A and G antibody titers

To evaluate the reliability of Chlamydia pneumoniae-specific immunoglobulin G (IgG) and IgA antibody titers as measured by the microimmunofluorescence (MIF) test, we compared results from 392 individuals using a standard MIF protocol at two academic laboratories. The kappas for dichotomous titers (>/=16 versus <16) were 0.39 for IgA and 0.53 for IgG. Measurement error likely attenuates C. pneumoniae-disease associations; the magnitude of attenuation can be estimated from results of studies such as this one.

The Beta-Carotene and Retinol Efficacy Trial: incidence of lung cancer and cardiovascular disease mortality during 6-year follow-up after stopping beta-carotene and retinol supplements

BACKGROUND

The Beta-Carotene and Retinol Efficacy Trial (CARET) tested the effect of daily beta-carotene (30 mg) and retinyl palmitate (25,000 IU) on the incidence of lung cancer, other cancers, and death in 18,314 participants who were at high risk for lung cancer because of a history of smoking or asbestos exposure. CARET was stopped ahead of schedule in January 1996 because participants who were randomly assigned to receive the active intervention were found to have a 28% increase in incidence of lung cancer, a 17% increase in incidence of death and a higher rate of cardiovascular disease mortality compared with participants in the placebo group.

METHODS

After the intervention ended, CARET participants returned the study vitamins to their study center and provided a final blood sample. They continue to be followed annually by telephone and mail self-report. Self-reported cancer endpoints were confirmed by review of pathology reports, and death endpoints were confirmed by review of death certificates. All statistical tests were two-sided.

RESULTS

With follow-up through December 31, 2001, the post-intervention relative risks of lung cancer and all-cause mortality for the active intervention group compared with the placebo group were 1.12 (95% confidence interval [CI] = 0.97 to 1.31) and 1.08 (95% CI = 0.99 to 1.17), respectively. Smoothed relative risk curves for lung cancer incidence and all-cause mortality indicated that relative risks remained above 1.0 throughout the post-intervention follow-up. By contrast, the relative risk of cardiovascular disease mortality decreased rapidly to 1.0 after the intervention was stopped. During the post-intervention phase, females had larger relative risks of lung cancer mortality (1.33 versus 1.14; P = .36), cardiovascular disease mortality (1.44 versus 0.93; P = .03), and all-cause mortality (1.37 versus 0.98; P = .001) than males.

CONCLUSIONS

The previously reported adverse effects of beta-carotene and retinyl palmitate on lung cancer incidence and all-cause mortality in cigarette smokers and individuals with occupational exposure to asbestos persisted after drug administration was stopped although they are no longer statistically significant. Planned subgroup analyses suggest that the excess risks of lung cancer were restricted primarily to females, and cardiovascular disease mortality primarily to females and to former smokers.

Physical Activity in Relation to All-Site and Lung Cancer Incidence and Mortality in Current and Former Smokers

Increased physical activity has been associated with a reduction in the incidence and mortality from all-site cancer and some site-specific cancers in samples of primarily nonsmoking individuals; however, little is known about whether physical activity is associated with similar risk reductions among smokers and ex-smokers. This study examined physical activity in relation to all-site cancer and lung cancer incidence and mortality in a sample of current and former smokers (n = 7,045; 59% male; 95% Caucasian; mean age, 63 years) drawn from the β-Carotene and Retinol Efficacy Trial, a lung cancer chemoprevention trial. Hazard rate ratios and 95% confidence intervals associated with a 1 SD increase in physical activity were 0.86 (0.80-0.94) for all-site cancer only among men, 0.84 (0.69-1.03) for lung cancer only for younger participants, 0.75 (0.59-0.94) for cancer mortality among younger participants and 0.68 (0.53-0.89) among women, and 0.69 (0.53-0.90) for lung cancer mortality only among women. These results suggest that incidence may be more attenuated by physical activity for men and mortality more attenuated for women. Effects may be more pronounced for younger people and may differ inconsistently by pack-years of smoking. Physical activity may play a role in reducing cancer risk and mortality among those with significant tobacco exposure. Prospective studies using more sophisticated measures of physical activity assessed at multiple time points during follow-up are needed to corroborate these associations.

Physical activity in relation to all-site and lung cancer incidence and mortality in current and former smokers

Increased physical activity has been associated with a reduction in the incidence and mortality from all-site cancer and some site-specific cancers in samples of primarily nonsmoking individuals; however, little is known about whether physical activity is associated with similar risk reductions among smokers and ex-smokers. This study examined physical activity in relation to all-site cancer and lung cancer incidence and mortality in a sample of current and former smokers (n = 7,045; 59% male; 95% Caucasian; mean age, 63 years) drawn from the beta-Carotene and Retinol Efficacy Trial, a lung cancer chemoprevention trial. Hazard rate ratios and 95% confidence intervals associated with a 1 SD increase in physical activity were 0.86 (0.80-0.94) for all-site cancer only among men, 0.84 (0.69-1.03) for lung cancer only for younger participants, 0.75 (0.59-0.94) for cancer mortality among younger participants and 0.68 (0.53-0.89) among women, and 0.69 (0.53-0.90) for lung cancer mortality only among women. These results suggest that incidence may be more attenuated by physical activity for men and mortality more attenuated for women. Effects may be more pronounced for younger people and may differ inconsistently by pack-years of smoking. Physical activity may play a role in reducing cancer risk and mortality among those with significant tobacco exposure. Prospective studies using more sophisticated measures of physical activity assessed at multiple time points during follow-up are needed to corroborate these associations.

Chlamydia pneumoniae infection and risk of lung cancer

Infection with Chlamydia pneumoniae may be associated with an increased risk of lung cancer. We conducted a matched case-control study (508 pairs) nested within a large prospective study to investigate whether IgA antibody titers to C. pneumoniae measured by the microimmunofluorescence test are associated with lung cancer risk after controlling for confounders. Individuals with antibody titers > or = 16 had 1.2 times the risk of lung cancer (95% confidence interval, 0.9-1.6) compared to those with lower titers. There was a significant trend (P = 0.007) of increasing odds ratios with increasing IgA titers primarily due to an odds ratio of 2.8 (95% confidence interval, 1.1-6.7) associated with titers > or = 256. Lung cancer risk associated with IgA titers > or = 16 was stronger among former smokers. To better understand predictors of IgA seropositivity, we also examined demographic, lifestyle, dietary, and medical correlates of IgA titers > or = 16 among controls. Those with race not classified as White or Black were more likely to have IgA titers > or = 16; there were no significant differences in seropositivity by smoking behaviors. In summary, the adjusted odds ratio for lung cancer associated with IgA titers > or = 16 was compatible with a weakly positive association, although nondifferential measurement error of antibody titers may have resulted in a conservative bias. Future studies using precise measures of chronic C. pneumoniae status are needed to better determine the role of this organism in the etiology of lung cancer.

Chlamydia pneumoniae Infection and Risk of Lung Cancer

Infection with Chlamydia pneumoniae may be associated with an increased risk of lung cancer. We conducted a matched case-control study (508 pairs) nested within a large prospective study to investigate whether IgA antibody titers to C. pneumoniae measured by the microimmunofluorescence test are associated with lung cancer risk after controlling for confounders. Individuals with antibody titers ≥16 had 1.2 times the risk of lung cancer (95% confidence interval, 0.9-1.6) compared to those with lower titers. There was a significant trend (P = 0.007) of increasing odds ratios with increasing IgA titers primarily due to an odds ratio of 2.8 (95% confidence interval, 1.1-6.7) associated with titers ≥256. Lung cancer risk associated with IgA titers ≥16 was stronger among former smokers. To better understand predictors of IgA seropositivity, we also examined demographic, lifestyle, dietary, and medical correlates of IgA titers ≥16 among controls. Those with race not classified as White or Black were more likely to have IgA titers ≥16; there were no significant differences in seropositivity by smoking behaviors. In summary, the adjusted odds ratio for lung cancer associated with IgA titers ≥16 was compatible with a weakly positive association, although nondifferential measurement error of antibody titers may have resulted in a conservative bias. Future studies using precise measures of chronic C. pneumoniae status are needed to better determine the role of this organism in the etiology of lung cancer.

Serum protein expression profiling for cancer detection: validation of a SELDI-based approach for prostate cancer

Multiple studies have reported that analysis of serum and other bodily fluids using surface enhanced laser desorption/ionization time of flight mass spectroscopy (SELDI-TOF-MS) can identify a "fingerprint" or "signature" of spectral peaks that can separate patients with a specific disease from normal control patients. Ultimately, classification by SELDI-TOF-MS relies on spectral differences in position and amplitude of resolved peaks. Since the reproducibility of quantitation, resolution and mass accuracy of the SELDI-TOF-MS, or any high throughput mass spectrometric technique, has never been determined this method has come under some skepticism as to its clinical usefulness. This manuscript describes a detailed design of a three-phase study to validate the clinical usefulness of SELDI-TOF-MS in the identification of patients with prostatic adenocarcinoma (PCA). At the end of this validation study, the usefulness of the general SELDI-TOF-MS approach to identifying patients with PCA will be demonstrated and how it compares with PCA diagnosis by measuring prostate specific antigen.

Is olestra consumption associated with changes in dietary intake, serum lipids, and body weight?

OBJECTIVES

There is considerable controversy regarding the effects of fat substitutes (such as the non-caloric fat substitute, olestra) on Americans' diet and health. This report gives associations of olestra consumption (in savory snacks) with changes in nutrient intake, serum lipid concentrations, and body weight 1 y after these snacks became available nationally in the United States.

METHODS

Participants were 1178 adults recruited from three large U.S. cities. At baseline (before the availability of olestra), participants attended a clinic visit and completed questionnaires (including a food-frequency questionnaire), provided fasting blood samples, and had height and weight measured. The clinic visit was repeated about 1 y later, after the introduction of olestra-containing snacks in the marketplace. Olestra consumption was categorized as "none," "very low" (>0 to <0.4 g/d), "low" (>/=0.4 to <2.0 g/d), and "moderate/high" (>/=2.0 g/d).

RESULTS

Twenty-five percent of participants reported consuming olestra-containing savory snacks in the preceding month, but only 2% were categorized as moderate/high consumers. Men reported nearly twice as much olestra consumption as women (1.22 versus 0.68 g/d, P = 0.01). Among moderate/high olestra consumers, total energy and carbohydrate intakes increased by 209 kcal/d and 37 g/d, compared with decreases of 87 kcal/d and 14 g/d, respectively, among non-consumers (both Ps for trend = 0.01), corresponding to non-significant changes in percentages of energy from carbohydrate and total fat. Olestra consumption was not associated with statistically significant changes in serum lipids or body weight.

CONCLUSIONS

This study found very modest changes in total diet, but no changes in serum lipids or body weight, associated with consumption of olestra-containing savory snacks. However, the low use of olestra by the study sample limited the ability of this study to detect significant effects.

Reliability and validity of self-report of vitamin and mineral supplement use in the vitamins and lifestyle study

In the United States, dietary supplements contribute a large proportion of micronutrient intakes. Therefore, it is important to collect accurate information on supplement use for studies of micronutrients and disease risk. This report describes the test-retest reliability and validity of a detailed, self-administered mailed questionnaire on vitamin and mineral supplement use. Participants (n = 220) completed the questionnaire at baseline and 3 months later. During an in-person interview, participants provided spot urine and blood samples, and interviewers transcribed nutrient information from their supplement bottle labels. The questionnaire had very good test-retest reliability for mean supplement intake over the past 10 years, with intraclass correlations ranging from 0.69 for beta-carotene to 0.87 for vitamin E. Pearson's correlation coefficients comparing current supplemental intakes from the questionnaire and interviews/label transcriptions were high, ranging from 0.58 for beta-carotene to 0.82 for chromium; however, for some nutrients, median intakes from the questionnaire were slightly lower than from the interviews. Beta-carotene, vitamin C, and vitamin E (alpha-tocopherol) showed clear linear trends of increasing blood concentrations with higher self-reported supplemental intakes (Pearson's correlation coefficients adjusted for potential confounding factors and diet = 0.31, 0.29, and 0.69, respectively; all p < 0.0001). Creatinine-adjusted spot urinary calcium values were not associated with supplemental calcium intakes (Pearson's r = -0.07). This self-administered questionnaire demonstrated high reproducibility and validity for collecting detailed information on supplement use.

Fruits and vegetables are associated with lower lung cancer risk only in the placebo arm of the beta-carotene and retinol efficacy trial (CARET)

Despite the unexpected results from the beta-Carotene and Retinol Efficacy Trial (CARET) and similar supplementation trials showing that supplementation with beta-carotene increased, rather than decreased, lung cancer incidence, considerable interest remains in investigating how other compounds in fruits and vegetables may affect lung cancer risk. We used data from 14,120 CARET participants who completed food frequency questionnaires to examine associations of diet with lung cancer risk. After 12 years of follow-up (1989-2001), 742 participants developed lung cancer. We used Cox proportional hazards models to estimate multivariate relative risks (RRs) and 95% confidence intervals (CIs). Analyses were controlled for smoking, asbestos exposure, and other covariates. Analyses of specific botanical groups were also controlled for total fruit and vegetable intake. All models were stratified by CARET treatment arm, and all statistical tests were two-sided. Statistically significant associations of fruit and vegetable intake with lower lung cancer risk were restricted to the CARET placebo arm. The RR for highest versus lowest quintile of total fruit consumption in the placebo arm was 0.56 (95% CI, 0.39-0.81) with a two-sided P for trend = 0.003. Two specific botanical groups were associated with reduced risk of lung cancer. Compared with the lowest quintile of rosaceae fruit consumption, placebo participants in the top quintile had a RR of 0.63 (95% CI, 0.42-0.94; P for trend = 0.02); for cruciferae vegetables, the RR was 0.68 (95% CI, 0.45-1.04; P for trend = 0.01). We did not observe any statistically significant associations of fruit and vegetable intake with lung cancer risk among participants randomized to receive the CARET supplements (30 mg of beta-carotene and 25,000 IU of retinyl palmitate). This report provides evidence that plant foods have an important preventive influence in a population at high risk for lung cancer. However, persons who use beta-carotene supplements do not benefit from the protective compounds in plant foods.

Variations in lung cancer risk among smokers

BACKGROUND

Although there is no proven benefit associated with screening for lung cancer, screening programs are attracting many individuals who perceive themselves to be at high risk due to smoking. We sought to determine whether the risk of lung cancer varies predictably among smokers.

METHODS

We used data on 18 172 subjects enrolled in the Carotene and Retinol Efficacy Trial (CARET)-a large, randomized trial of lung cancer prevention-to derive a lung cancer risk prediction model. Model inputs included the subject's age, sex, asbestos exposure history, and smoking history. We assessed the model's calibration by comparing predicted and observed rates of lung cancer across risk deciles and validated it by assessing the extent to which a model estimated on data from five CARET study sites could predict events in the sixth study site. We then applied the model to evaluate the risk of lung cancer among smokers enrolled in a study of lung cancer screening with computed tomography (CT).

RESULTS

The model was internally valid and well calibrated. Ten-year lung cancer risk varied greatly among participants in the CT study, from 15% for a 68-year-old man who has smoked two packs per day for 50 years and continues to smoke, to 0.8% for a 51-year-old woman who smoked one pack per day for 28 years before quitting 9 years earlier. Even among the subset of CT study participants who would be eligible for a clinical trial of cancer prevention, risk varied greatly.

CONCLUSIONS

The risk of lung cancer varies widely among smokers. Accurate risk prediction may help individuals who are contemplating voluntary screening to balance the potential benefits and risks. Risk prediction may also be useful for researchers designing clinical trials of lung cancer prevention.

Serum insulin-like growth factor (IGF) and IGF-binding protein levels and risk of lung cancer: a case-control study nested in the beta-Carotene and Retinol Efficacy Trial Cohort

Recent prospective studies have suggested that insulin-like growth factor (IGF)-I levels are related to risk of some epithelial cancers. We previously reported in a case-control study a significant association between IGF-I level and lung cancer risk, with a 2-fold increased risk in the highest quartile. We now report the results of a lung cancer case-control study nested in the placebo arm of the beta-Carotene and Retinol Efficacy Trial in heavy smokers. We identified 159 cases for whom sera had been collected at least 3 years before diagnosis and for whom 2 suitable controls/case (final number, 297) could be matched from the same study arm on age (within 5-year intervals), sex, ethnicity, year of enrollment into the beta-Carotene and Retinol Efficacy Trial, year of blood draw, and exposure category (smoking or asbestos). The cases were significantly heavier smokers than the controls (mean pack-years, 58.7 and 45.9, respectively; P < 0.001). An inverse relationship between IGF-I level and age was evident only for former smokers, and not for those who were current smokers at the time of blood draw. Both IGF-I and IGF-binding protein (IGFBP)-3 levels were higher in cases than in controls, but none of the differences achieved statistical significance. The odds ratios for IGF-I were around unity, except for subsets of heaviest smokers and those who had quit smoking for the longest period of time, in whom there were elevated risks in the second to fourth quartiles of IGF-I relative to the first quartile (odds ratios, 2.21-2.91), although again, none achieved statistical significance. For younger subjects, IGF-I was inversely associated with lung cancer risk in the models that also controlled for IGFBP-3. Elevated risks for lung cancer were noted in the highest quartile of IGFBP-3 level, and these tended to be higher in current smokers and more recent quitters. These results do not support the conclusions of our prior case-control study. It is possible that current smoking or recent cessation may exert a suppressive effect on IGF-I levels (notably in younger subjects with higher baseline levels) that may obscure a relatively modest association between IGF-I level and lung cancer risk. On the other hand, risks associated with elevated IGFBP-3 level tended to be higher in current smokers and more recent quitters. This trend toward a positive association with IGFBP-3 level is unexpected and requires further investigation. Finally, from these data, we cannot exclude the possibility that risk of lung cancer in nonsmokers may be related to IGF-I levels.