Beta-Carotene Cancer Prevention Study Research Articles

A prospective study of smoking-related white blood cell DNA methylation markers and risk of bladder cancer

Bladder cancer, a common neoplasm, is primarily caused by tobacco smoking. Epigenetic alterations including DNA methylation have the potential to be used as prospective markers of increased risk, particularly in at-risk populations such as smokers. We aimed to investigate the potential of smoking-related white blood cell (WBC) methylation markers to contribute to an increase in bladder cancer risk prediction over classical questionnaire-based smoking metrics (i.e., duration, intensity, packyears) in a nested case–control study within the prospective prostate, lung, colorectal, and ovarian (PLCO) Cancer Screening Trial and the alpha-tocopherol, beta-carotene cancer (ATBC) Prevention Study (789 cases; 849 controls). We identified 200 differentially methylated sites associated with smoking status and 28 significantly associated (after correction for multiple testing) with bladder cancer risk among 2670 previously reported smoking-related cytosine–phosphate–guanines sites (CpGs). Similar patterns were observed across cohorts. Receiver operating characteristic (ROC) analyses indicated that cg05575921 (AHHR), the strongest smoking-related association we identified for bladder cancer risk, alone yielded similar predictive performance (AUC: 0.60) than classical smoking metrics (AUC: 0.59–0.62). Best prediction was achieved by including the first principal component (PC1) from the 200 smoking-related CpGs alongside smoking metrics (AUC: 0.63–0.65). Further, PC1 remained significantly associated with elevated bladder cancer risk after adjusting for smoking metrics. These findings suggest DNA methylation profiles reflect aspects of tobacco smoke exposure in addition to those captured by smoking duration, intensity and packyears, and/or individual susceptibility relevant to bladder cancer etiology, warranting further investigation.

Abstract 3427: Serum metabolites and pancreatic ductal adenocarcinoma in two prospective cohorts

Abstract Objective: Metabolomics may provide insight to understand the etiology and potential mechanisms for pancreatic ductal adenocarcinoma (PDAC) development beyond established risk factors of smoking, diabetes, and adiposity. We extended our previous metabolomic study by including additional participants from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) with the aim to examine prospective associations between serum metabolites and incident PDAC. Method: We measured 1483 known metabolites in pre-diagnostic serum (up to 24 years) in two PDAC nested case-control studies within the PLCO (360 cases-control pairs) of mostly non-smoker men and women and Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC, 372 cases-control pairs) male smokers using liquid chromatography, high resolution/accurate mass spectrometry. Controls were incidence-density sampled and matched to cases by age, blood draw date, sex, race/ethnicity, and cohort. We used conditional logistic regression to calculate odds ratios and 95% confidence intervals for PDAC per standard deviation increase in log10-metabolite levels in each cohort and combined using fixed-effect meta-analyses and stratified by follow-up time. We also performed ElasticNet regression in each cohort to identify metabolites. We assessed associations of 72 predefined metabolic pathways with PDAC by comparing Fisher’s statistic of metabolite p-values per pathway with a null distribution based on 500,000 permutations. Results: Sixty-six metabolites were associated with PDAC at a false discovery rate (FDR)<0.05 with 26 below the Bonferroni threshold (P<3.4 × 10−5). Among the 66 metabolites, 14 and 15 were selected in ElasticNet regressions in ATBC and PLCO, respectively, with two in both cohorts. Notable findings include: fibrinopeptide B(1-9); seven modified, di- or poly-peptides; eight xenobiotics related to tobacco smoke; amino acids, carbohydrates, and TCA cycle metabolites known to be regulated by mutant KRAS (aspartate, glutamate, lactate, pyruvate, and α-ketoglutarate); four secondary bile acids and three aromatic amino acids (tryptophan, phenylalanine, and tyrosine) that were positively, while four fibrinogen cleavage peptides were inversely associated with PDAC. Among the top identified metabolites, aspartate, α-glutamyltyrosine, pyroglutamylglutamine, and Glu-Gly-Asn-Val showed time-varying associations overall (P≤0.05) with greater magnitudes within the first 5 years after blood draw. Thirteen metabolic pathways were associated with PDAC (Bonferroni P≤0.05). Conclusion: Our study suggests pre-diagnostic circulating metabolites, particularly those potentially related to subclinical disease, microbiome, and tobacco metabolism are associated with PDAC. The identified metabolites along with other known risk factors might be useful in algorithms to model disease risk and progression. Citation Format: Ting Zhang, Steven C. Moore, Sheng Fu, Kevin Wang, Demetrius Albanes, Stephanie J. Weinstein, Kai Yu, Rachael Z. Stolzenberg-Solomon. Serum metabolites and pancreatic ductal adenocarcinoma in two prospective cohorts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3427.

Fiber and whole grain intakes in relation to liver cancer risk: An analysis in 2 prospective cohorts and systematic review and meta-analysis of prospective studies.

The association between fiber or whole grain intakes and the risk of liver cancer remains unclear. We assessed the associations between fiber or whole grain intakes and liver cancer risk among 2 prospective studies, and systematically reviewed and meta-analyzed these results with published prospective studies. A total of 111,396 participants from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) and 26,085 men from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study were included. Intakes of total fiber and whole grains were estimated from validated food frequency questionnaires. Study-specific HRs and 95% CI with liver cancer risk were estimated using multivariable-adjusted Cox regression. We systematically reviewed existing literature, and studies were combined in a dose-response meta-analysis. A total of 277 (median follow-up = 15.6 y) and 165 (median follow-up = 16.0 y) cases of liver cancer were observed in Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial and Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, respectively. Dietary fiber was inversely associated with liver cancer risk in Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (HR 10g/day : 0.69; 95% CI: 0.55-0.86). No significant associations were observed between whole grain intakes and liver cancer risk in either study. Our meta-analysis included 2383 incident liver cancer cases (7 prospective cohorts) for fiber intake and 1523 cases (5 prospective cohorts) for whole grain intake; combined HRs for liver cancer risk were 0.83 (0.76-0.91) per 10 g/day of fiber and 0.92 (0.85-0.99) per 16 g/day (1 serving) of whole grains. Dietary fiber and whole grains were inversely associated with liver cancer risk. Further research exploring potential mechanisms and different fiber types is needed.

Changes in smoking use and subsequent lung cancer risk in the ATBC study.

Reducing cigarettes/day may lower the risk of lung cancer compared with continuing to smoke at the same intensity. Other changes in smoking behaviors, such as increasing cigarette consumption or quitting for a period and relapsing, may also affect lung cancer risk. We examined changes in smoking status and cigarettes/day among 24,613 Finnish male smokers aged 50-69 years who participated in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. Longitudinal data on smoking were collected during study follow-up visits three times a year (approximately every 4 months) between 1985 and 1993. Incident lung cancer cases through 2012 were identified by the Finnish Cancer Registry. Risk ratios (RRs) and 95% confidence intervals (95%CI) were estimated using Cox proportional hazards regression. Compared with smoking 20 cigarettes/day continuously across the intervention period, reducing an average of 5 cigarettes/day per year while smoking was associated with a 20% lower risk of lung cancer (95%CI : 0.71 to 0.90). A substantially lower risk of lung cancer was also observed when participants smoked at 50% (RR = 0.72; 95%CI : 0.57-0.90) and 10% (RR = 0.55; 95%CI : 0.36-0.83) of study visits, relative to smoked at 100% of study visits. Smokers may lower their risk of lung cancer by reducing smoking intensity (cigarettes per day while smoking) and the time they smoke. However, quitting smoking completely is the most effective way for smokers to reduce their risk of lung cancer.

Abstract A017: Lipidomic biomarkers of usual alcohol use and their association with pancreatic ductal adenocarcinoma risk

Abstract There is suggestive epidemiologic evidence for an association between alcohol use and pancreatic ductal adenocarcinoma (PDAC). Previous studies reported alcohol use to be associated with high-density lipoprotein and fatty acyl ethyl esters. Lipidomic metabolites may improve assessment of self-reported alcohol use and provide mechanistic insights for the alcohol-PDAC association. We aimed to identify lipidomic signatures of self-reported alcohol use and evaluate their associations with PDAC risk using comprehensive lipidomic measures from nested case-control studies within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial cohorts (716 case-control sets). Controls were matched to cases (1:1) by age, sex, race, date of blood draw and cohort. Serum samples and self-reported alcohol use were collected at baseline up to 24 years before PDAC diagnosis. Absolute concentrations of 611 lipid species across 15 classes were measured on the Complex Lipid Panel (Lipidizer Sciex SelexIon-5500 QTRAP platform) and grouped into 161 class-specific fatty acids (FA) and 28 total FAs. We conducted cross-sectional analyses using linear regression to identify associations between log-transformed alcohol and 1-standard deviation (SD) increase in log-lipid concentrations among controls within each cohort. Conditional logistic regression and fixed-effects meta-analysis were used to calculate PDAC odds ratios (OR) per 1-SD increase in the log-concentration identified alcohol-lipidomic metabolites in common in both cohorts. All models were adjusted for age, smoking, BMI, height, diabetes, education, and diet quality. Alcohol was associated with 36 species, 13 class-specific FAs and 3 total FAs at Bonferroni thresholds <8.18 × 10−5, <3.11 × 10−4, and <1.79 × 10−3, respectively. These belonged to ceramides, cholesterylesters, diacylglycerols, hexosylceramides, lactosylceramides, lysophosphatidylcholines, phosphatidylcholines, phospatidylethanolamines, phosphatidylinositols, and triacylglycerols lipid classes, and mostly holding FA15:0 (pentadecanoic acid), FA17:0 (margaric acid) and FA18:2 (linoleic acid). Nine triacylglycerols (TAG(49:3-FA18:2), TAG(51:3-FA18:2), TAG(49:2-FA18:2), TAG(49:3-FA15:0), TAG(51:3-FA15:0), TAG(51:4-FA18:3), TAG(51:2-FA18:2), TAG(51:5-FA18:3), TAG(51:2-FA15:0)) and one phosphatidylcholine (PC(15:0/18:2)) lipid species and one total FA (FA15:0) showed significant inverse associations with PDAC with ORs ranging from 0.82 to 0.86 (FDR<0.10). There was no association between class-specific FAs and PDAC. Our results support the hypothesis that alcohol use is associated with serum lipid species from 10 lipid classes, mostly with FA15:0, FA17:0 and FA18:2. Nine triacylglycerols, one phosphatidylcholine and total FA15:0 showed inverse prospective associations with PDAC, the latter having been shown to decrease inflammation and regulate glucose metabolism in previous studies. These findings may help understand the inconsistent association between alcohol use and PDAC. Citation Format: Sabine Naudin, Paloma Mitra, Ting Zhang, Demetrius Albanes, Steven C. Moore, Rachael Stolzenberg-Solomon. Lipidomic biomarkers of usual alcohol use and their association with pancreatic ductal adenocarcinoma risk [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A017.

Identification of pre-diagnostic lipid sets associated with liver cancer risk using untargeted lipidomics and chemical set analysis: A nested case-control study within the ATBC cohort.

In pre-disposed individuals, a reprogramming of the hepatic lipid metabolism may support liver cancer initiation. We conducted a high-resolution mass spectrometry based untargeted lipidomics analysis of pre-diagnostic serum samples from a nested case-control study (219 liver cancer cases and 219 controls) within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. Out of 462 annotated lipids, 158 (34.2%) were associated with liver cancer risk in a conditional logistic regression analysis at a false discovery rate (FDR) <0.05. A chemical set enrichment analysis (ChemRICH) and co-regulatory set analysis suggested that 22/28 lipid classes and 47/83 correlation modules were significantly associated with liver cancer risk (FDR <0.05). Strong positive associations were observed for monounsaturated fatty acids (MUFA), triacylglycerols (TAGs) and phosphatidylcholines (PCs) having MUFA acyl chains. Negative associations were observed for sphingolipids (ceramides and sphingomyelins), lysophosphatidylcholines, cholesterol esters and polyunsaturated fatty acids (PUFA) containing TAGs and PCs. Stearoyl-CoA desaturase enzyme 1 (SCD1), a rate limiting enzyme in fatty acid metabolism and ceramidases seems to be critical in this reprogramming. In conclusion, our study reports pre-diagnostic lipid changes that provide novel insights into hepatic lipid metabolism reprogramming may contribute to a pro-cell growth and anti-apoptotic tissue environment and, in turn, support liver cancer initiation.

Mitochondrial DNA Fragmentation and Risk of Non-Hodgkin Lymphoma

Research suggests that increased mitochondrial DNA copy number (mtDNAcn) is associated with increased risk of non-Hodgkin lymphoma (NHL); however, no studies to date have evaluated whether the mitochondrial DNA fraction with breaks (mtDNAfb) is associated with risk of NHL. To evaluate the association of mtDNAfb with NHL risk. This nested case-control study, which used prospectively collected samples as part of baseline enrollment (from 1985 through 1988) of 29 133 men who smoked for the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study conducted in southwest Finland, included 107 incident NHL cases and 107 controls (matched on date of birth ±5 years). Analyses were conducted from January to September 2022. High-throughput real-time polymerase chain reaction assays quantifying mtDNAfb. Incident NHL cases were identified in the ATBC Study through April 30, 2002, using the Finnish Cancer Registry and the Register of Causes of Death. The mtDNAfb was quantified and categorized based on the median, tertile, and quartile distributions among controls. Odds ratios (ORs) and 95% CIs were estimated using conditional logistic regression models to assess the associations between categorized mtDNAfb and future risk of NHL, controlling for age, body mass index, number of cigarettes smoked per day, number of pack-years, and mtDNAcn. A total of 29 133 men (median [IQR] age, 57.2 [52.6-62.5] years) participated in ATBC Study. Higher mtDNAfb was associated with an increased risk of NHL (median OR, 2.89; 95% CI, 1.40-5.93) in a dose-dependent manner (quartile 2 vs 1 OR, 1.24; 95% CI, 0.43-3.40; quartile 3 vs 1 OR, 3.58; 95% CI, 1.39-9.24; quartile 4 vs 1 OR, 3.42; 95% CI, 1.30- 8.99; P = .004 for trend). This study's findings suggest that increased mtDNAfb is associated with an increased future risk of NHL. Additional studies are needed to confirm these findings, particularly among women and nonsmokers.

Circulating hormones and risk of gastric cancer by subsite in three cohort studies

BackgroundObesity has been positively associated with gastric cancer. Excess fat impacts hormones, which have been implicated in carcinogenesis. We investigated obesity-related hormones and cardia gastric cancer (CGC) and non-cardia gastric cancer (NCGC) risk.MethodsNested case–control studies were conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort (61 CGCs, and 172 NCGCs and matched controls) and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) study (100 CGCs and 65 NCGCs and matched controls); serum hormones were measured. In UK-Biobank (n = 458,713), we included 137 CGCs and 92 NCGCs. Sex-specific analyses were conducted. For EPIC and ATBC, odds ratios (ORs), and for UK-Biobank hazard ratios (HRs), were estimated using conditional logistic regression and Cox regression, respectively.ResultsInsulin-like growth-factor-1 was positively associated with CGC and NCGC in EPIC men (ORper 1-SD increase 1.94, 95% CI 1.03–3.63; ORper 1-SD increase 1.63, 95% CI 1.05–2.53, respectively), with similar findings for CGC in UK-Biobank women (HRper 1-SD increase 1.76, 95% CI 1.08–2.88). Leptin in EPIC men and C-peptide in EPIC women were positively associated with NCGC (ORT3 vs. T1 2.72, 95% CI 1.01–7.34 and ORper 1-SD increase 2.17, 95% CI 1.19–3.97, respectively). Sex hormone-binding globulin was positively associated with CGC in UK-Biobank men (HRper 1-SD increase 1.29, 95% CI 1.02–1.64). Conversely, ghrelin was inversely associated with NCGC among EPIC and ATBC men (ORper 1-SD increase 0.53, 95% CI 0.34–0.84; ORper 1-SD increase 0.22, 95% CI 0.10–0.50, respectively). In addition, dehydroepiandrosterone was inversely associated with CGC in EPIC and ATBC men combined.ConclusionsSome obesity-related hormones influence CGC and NCGC risk.

Dietary Quality and Circulating Lipidomic Profiles in 2 Cohorts of Middle-Aged and Older Male Finnish Smokers and American Populations

BackgroundHigher dietary quality is associated with lower disease risks and has not been examined extensively with lipidomic profiles. ObjectivesOur goal was to examine associations of the Healthy Eating Index (HEI)-2015, Alternate HEI-2010 (AHEI-2010), and alternate Mediterranean Diet Index (aMED) diet quality indices with serum lipidomic profiles. MethodsWe conducted a cross-sectional analysis of HEI-2015, AHEI-2010, and aMED with lipidomic profiles from 2 nested case-control studies within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (n = 627) and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (n = 711). We used multivariable linear regression to determine associations of the indices, derived from baseline food-frequency questionnaires (Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial: 1993–2001, Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study: 1985–1988) with serum concentrations of 904 lipid species and 252 fatty acids (FAs) across 15 lipid classes and 28 total FAs, within each cohort and meta-analyzed results using fixed-effect models for lipids significant at Bonferroni-corrected threshold in common in both cohorts. ResultsAdherence to HEI-2015, AHEI-2010, or aMED was associated positively with 31, 41, and 54 lipid species and 8, 6, and 10 class-specific FAs and inversely with 2, 8, and 34 lipid species and 1, 3, and 5 class-specific FAs, respectively. Twenty-five lipid species and 5 class-specific FAs were common to all indices, predominantly triacylglycerols, FA22:6 [docosahexaenoic acid (DHA)]-containing species, and DHA. All indices were positively associated with total FA22:6. AHEI-2010 and aMED were inversely associated with total FA18:1 (oleic acid) and total FA17:0 (margaric acid), respectively. The identified lipids were most associated with components of seafood and plant proteins and unsaturated:saturated fat ratio in HEI-2015; eicosapentaenoic acid plus DHA in AHEI-2010; and fish and monounsaturated:saturated fat ratio in aMED. ConclusionsAdherence to HEI-2015, AHEI-2010, and aMED is associated with serum lipidomic profiles, mostly triacylglycerols or FA22:6-containing species, which are related to seafood and plant proteins, eicosapentaenoic acid-DHA, fish, or fat ratio index components.

Lipidomics and pancreatic cancer risk in two prospective studies.

Pancreatic ductal carcinoma (PDAC) is highly fatal with limited understanding of mechanisms underlying its carcinogenesis. We comprehensively investigated whether lipidomic measures were associated with PDAC in two prospective studies. We measured 904 lipid species and 252 fatty acids across 15 lipid classes in pre-diagnostic serum (up to 24years) in a PDAC nested-case control study within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO, NCT00002540) with 332 matched case-control sets including 272 having serial blood samples and Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC, NCT00342992) with 374 matched case-control sets. Controls were matched to cases by cohort, age, sex, race, and date at blood draw. We used conditional logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI) per one-standard deviation increase in log-lipid concentrations within each cohort, and combined ORs using fixed-effects meta-analyses. Forty-three lipid species were associated with PDAC (false discovery rate, FDR ≤ 0.10), including lysophosphatidylcholines (LPC, n = 2), phosphatidylethanolamines (PE, n = 17), triacylglycerols (n = 13), phosphatidylcholines (PC, n = 3), diacylglycerols (n = 4), monoacylglycerols (MAG, n = 2), cholesteryl esters (CE, n = 1), and sphingomyelins (n = 1). LPC(18:2) and PE(O-16:0/18:2) showed significant inverse associations with PDAC at the Bonferroni threshold (P value < 5.5 × 10-5). The fatty acids LPC[18:2], LPC[16:0], PC[15:0], MAG[18:1] and CE[22:0] were significantly associated with PDAC (FDR < 0.10). Similar associations were observed in both cohorts. There was no significant association for the differences between PLCO serial lipidomic measures or heterogeneity by follow-up time overall. Results support that the pre-diagnostic serum lipidome, including 43 lipid species from 8 lipid classes and 5 fatty acids, is associated with PDAC.

Abstract 6462: Cigarette smoking reduction and lung cancer risk in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study

Abstract Background. Cigarette smoking is a leading cancer risk factor. In addition to quitting smoking, reducing the number of cigarettes/day may decrease risk of lung cancer compared with continuing to smoke more heavily. However, few cohort studies have longitudinal assessments of cigarette use. Methods. We examined the association of changes in smoking status (trying to quit, not smoking at this time, and still smoking) and changes in cigarettes/day with subsequent incidence of lung cancer in 24,613 Finnish male participants of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, a cancer prevention trial of vitamin supplements that collected serial assessments of cigarette use. At baseline (1985-1988), all participants were current smokers 50-69 years old who smoked 5+ cigarettes/day. During the five-to-eight year intervention period, men were asked at 4-month intervals about changes in their smoking use since their last visit. We obtained individual estimates of the proportion of follow-up time (% of time) in each of the three smoking statuses, the transition probabilities between statuses and intercepts and slopes for the number of cigarettes/day. We then examined associations between changes in smoking and in cigarettes/day and subsequent incidence of lung cancer occurring between the end of the trial (April 30, 1993) and December 31, 2012. Using Cox regression, we modeled lung cancer risk ratios (RRs) and 95% confidence intervals (95%CI) associated with changes in smoking (% of time and number of cigarettes/day) relative to individuals who smoked 20 cigarettes/day across all the study visits. Models were additionally adjusted for age at the end of the trial, ATBC intervention group, education, and age at smoking initiation. Results. Overall, 3013 lung cancers were diagnosed during follow-up. The risk of lung cancer was lower among participants who reduced their smoking intensity by 5 or 10 cigarettes/day [RR=0.80(95%CI:0.71,0.89) and RR=0.64(95%CI:0.51,0.81), respectively]. RRs were further decreased among participants who also smoked at only 50% of study visits [-5 cigarettes/day RR=0.71(95%CI:0.57, 0.90) and -10 cigarettes/day RR=0.46(95%CI:0.44, 0.74)]. Individuals with the lowest risk were those who stopped smoking early at follow-up and continued to not smoke over the intervention period. For example, an individual who began the study smoking 15 cigarettes/day, stop smoking at 4 months and remained not smoking had a RR=0.24(95%CI: 0.11, 0.50). Conclusion: Even in the absence of cessation, smokers may meaningfully lower their lung cancer risk by reducing the number of cigarettes they smoke per day and the proportion of time they smoke. Yet, the lowest risk was observed among smokers who quit completely. Citation Format: Daniela S. Gutiérrez-Torres, Sungduk Kim, Paul Albert, Demetrius Albanes, Stephanie J. Weinstein, Maki Inoue-Choi, Neal D. Freedman. Cigarette smoking reduction and lung cancer risk in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6462.

Serum metabolomic profile of hair dye use

The International Agency for Research on Cancer reported that some chemicals in hair dyes are probably carcinogenic to those exposed to them occupationally. Biological mechanisms through which hair dye use may be related to human metabolism and cancer risk are not well-established. We conducted the first serum metabolomic examination comparing hair dye users and nonusers in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Metabolite assays were conducted using ultrahigh performance liquid chromatography-tandem mass spectrometry. The association between metabolite levels and hair dye use was estimated using linear regression, adjusting for age, body mass index, smoking, and multiple comparisons. Among the 1,401 detected metabolites, 11 compounds differed significantly between the two groups, including four amino acids and three xenobiotics. Redox-related glutathione metabolism was heavily represented, with L-cysteinylglycine disulfide showing the strongest association with hair dye (effect size (β) = − 0.263; FDR adjusted p-value = 0.0311), along with cysteineglutathione disulfide (β = − 0.685; FDR adjusted p-value = 0.0312). 5alpha-Androstan-3alpha,17beta-diol disulfate was reduced in hair dye users (β = − 0.492; FDR adjusted p-value = 0.077). Several compounds related to antioxidation/ROS and other pathways differed significantly between hair dye users and nonusers, including metabolites previously associated with prostate cancer. Our findings suggest possible biological mechanisms through which the use of hair dye could be associated with human metabolism and cancer risk.

Untargeted metabolomic profiling identifies serum metabolites associated with type 2 diabetes in a cross-sectional study of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study.

Type 2 diabetes (T2D) is a complex chronic disease with substantial phenotypic heterogeneity affecting millions of individuals. Yet, its relevant metabolites and etiological pathways are not fully understood. The aim of this study is to assess a broad spectrum of metabolites related to T2D in a large population-based cohort. We conducted a metabolomic analysis of 4,281 male participants within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. The serum metabolomic analysis was performed using an LC-MS/GC-MS platform. Associations between 1,413 metabolites and T2D were examined using linear regression, controlling for important baseline risk factors. Standardized β-coefficients and standard errors (SEs) were computed to estimate the difference in metabolite concentrations. We identified 74 metabolites that were significantly associated with T2D based on the Bonferroni-corrected threshold (P < 3.5 × 10-5). The strongest signals associated with T2D were of carbohydrates origin, including glucose, 1,5-anhydroglucitol (1,5-AG), and mannose (β = 0.34, -0.91, and 0.41, respectively; all P < 10-75). We found several chemical class pathways that were significantly associated with T2D, including carbohydrates (P = 1.3 × 10-11), amino acids (P = 2.7 × 10-6), energy (P = 1.5 × 10-4), and xenobiotics (P = 1.2 × 10-3). The strongest subpathway associations were seen for fructose-mannose-galactose metabolism, glycolysis-gluconeogenesis-pyruvate metabolism, fatty acid metabolism (acyl choline), and leucine-isoleucine-valine metabolism (all P < 10-8). Our findings identified various metabolites and candidate chemical class pathways that can be characterized by glycolysis and gluconeogenesis metabolism, fructose-mannose-galactose metabolism, branched-chain amino acids, diacylglycerol, acyl cholines, fatty acid oxidation, and mitochondrial dysfunction.NEW & NOTEWORTHY These metabolomic patterns may provide new additional evidence and potential insights relevant to the molecular basis of insulin resistance and the etiology of T2D.

Metabolomic profile of prostate cancer-specific survival among 1812 Finnish men

BackgroundAbnormal metabolism and perturbations in metabolic pathways play significant roles in the development and progression of prostate cancer; however, comprehensive metabolomic analyses of human data are lacking and needed to elucidate the interrelationships.MethodsWe examined the serum metabolome in relation to prostate cancer survival in a cohort of 1812 cases in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. Using an ultrahigh-performance LC-MS/MS platform, we identified 961 known metabolites in prospectively collected serum. Median survival time from diagnosis to prostate cancer-specific death (N=472) was 6.6 years (interquartile range=2.9–11.1 years). Cox proportional hazards regression models estimated hazard ratios and 95% confidence intervals of the associations between the serum metabolites (in quartiles) and prostate cancer death, adjusted for age at baseline and diagnosis, disease stage, and Gleason sum. In order to calculate risk scores, we first randomly divided the metabolomic data into a discovery set (70%) and validated in a replication set (30%).ResultsOverall, 49 metabolites were associated with prostate cancer survival after Bonferroni correction. Notably, higher levels of the phospholipid choline, amino acid glutamate, long-chain polyunsaturated fatty acid (n6) arachidonate (20:4n6), and glutamyl amino acids gamma-glutamylglutamate, gamma-glutamylglycine, and gamma-glutamylleucine were associated with increased risk of prostate cancer-specific mortality (fourth versus first quartile HRs=2.07–2.14; P-values <5.2×10−5). By contrast, the ascorbate/aldarate metabolite oxalate, xenobiotics S-carboxymethyl-L-cysteine, fibrinogen cleavage peptides ADpSGEGDFXAEGGGVR and fibrinopeptide B (1-12) were related to reduced disease-specific mortality (fourth versus first quartile HRs=0.82–0.84; P-value <5.2×10−5). Further adjustment for years from blood collection to cancer diagnosis, body mass index, smoking intensity and duration, and serum total and high-density lipoprotein cholesterol did not alter the results. Participants with a higher metabolic score based on the discovery set had an elevated risk of prostate cancer-specific mortality in the replication set (fourth versus first quartile, HR=3.9, P-value for trend<0.0001).ConclusionsThe metabolic traits identified in this study, including for choline, glutamate, arachidonate, gamma-glutamyl amino acids, fibrinopeptides, and endocannabinoid and redox pathways and their composite risk score, corroborate our previous analysis of fatal prostate cancer and provide novel insights and potential leads regarding the molecular basis of prostate cancer progression and mortality.

Abstract 5816: Serum metabolomic profile of exposure to hair dye

Abstract Hair dye products now represent one of the most rapidly growing beauty and personal care industries. The association between hair dye use and the development of cancer has been a research focus, including for breast, prostate, and bladder cancer, yet biological mechanisms have not been established. In this first examination of metabolomic response to hair dye exposure, we compared the serum metabolite profiles of male hair dye users and nonusers to identify differences related to biological mechanisms relevant to how exposure may influence cancer risk. The Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study was a randomized, controlled cancer prevention trial of vitamin supplementation that enrolled 50–69-year-old Finnish male smokers of whom 75 hair dye users and 125 nonusers were studied. Ultrahigh performance liquid chromatography-tandem mass spectrometry was used to assay baseline serum samples, and the difference in log-transformed, batch-normalized metabolite signals between the exposed and unexposed men was estimated using linear regression, adjusting for age, body mass index, and smoking. We measured 1,401 metabolites, of which 11 compounds, including 4 amino acids and 3 xenobiotics, differed significantly between the two groups after correction for multiple comparisons (FDR&amp;lt;0.1). Redox-related glutathione metabolism was heavily represented, including cysteineglutathione disulfide which showed the strongest association with hair dye use (effect size (β) = -0.685; p&amp;lt;0.0001), along with oxidized cysteine-glycine (β = -0.325; p&amp;lt;0.0001) and several compounds relevant to antioxidation/ROS pathways. Metabolites previously associated with prostate cancer risk also differed significantly between hair dye user and non-users. Our findings point to biological mechanisms through which exposure to hair dyes may impact risk of prostate and other cancers. Citation Format: Jungeun Lim, Jiaqi Huang, Stephanie J. Weinstein, Demetrius Albanes. Serum metabolomic profile of exposure to hair dye [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5816.

Abstract 2255: Alu retroelement copy number alterations and non-Hodgkin lymphoma

Abstract Background: Alu retrotransposons are repetitive DNA elements that make up nearly 10% of the human genome and reflect genomic instability. Genomic instability plays an important role in the pathogenesis of non-Hodgkin lymphoma (NHL). However, the relationship between Alu retrotransposons and future risk of NHL is unclear. Methods: We conducted a nested case-control study of NHL risk and Alu retroelement copy number within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) study, a prospective cohort with prediagnostic blood samples from 29,133 male Finnish smokers. We measured Alu copy number in 107 incident NHL cases and 1:1 matched controls (± 5 years age). DNA samples extracted from blood were assayed in triplicate using a monochrome multiplex quantitative polymerase chain reaction. We used the albumin gene for the single copy gene to control for genome content in samples. The odds ratios (OR) and 95% confidence intervals (CI) for all NHL were estimated using conditional logistic regression models, adjusting for age at randomization, number of cigarettes smoked per day and smoking duration. Polytomous logistic regression models were fit to compute ORs with Alu copy number for NHL subtypes. To determine if the association might be driven in part by elevated Alu copy number among undiagnosed cases at the time of blood sample collection, we excluded cases diagnosed within the first two years of follow-up. Results: Higher Alu copy number (using the median as the cut-point) was associated with an increased risk of NHL, both overall [OR, 95% CI=3.80 (1.76-8.17)] as well as for the diffuse large B-cell lymphoma [OR, 95% CI=4.83 (1.50-15.55)] and chronic lymphocytic leukemia/small lymphocytic lymphoma (SLL) [OR, 95% CI=2.66 (1.10-6.40)] subtypes. These associations were similar after excluding individuals diagnosed with NHL within two years after blood draw. Conclusions: These findings, which require replication, suggest that higher Alu copy number in prediagnostic leukocytes may play a role in the pathogenesis of NHL. Citation Format: Wei Hu. Alu retroelement copy number alterations and non-Hodgkin lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2255.

Abstract 2385: A prospective investigation of serum bile acids with risk of liver cancer, fatal liver disease, and biliary cancer

Abstract Abstract Background: Laboratory and emerging epidemiologic data suggest that bile acids (BAs), major regulators of the gut microbiota, play an important role in liver disease and cancer etiology. However, few epidemiologic studies have comprehensively examined associations between BAs and either liver endpoints or biliary cancer. Methods: In the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, we designed 1:1 matched nested case-control studies of primary liver cancer (n=247 cases), fatal liver disease (n=261 cases), and primary biliary cancer (n=92 cases). Using baseline serum collected ≤30 years prior to diagnosis or death, we measured concentrations of 15 BAs with liquid chromatography tandem mass spectrometry. We used multivariable conditional logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) between BAs and each endpoint, accounting for multiple comparisons. Results: Comparing the highest to the lowest quartile, ten BAs were positively associated with liver cancer risk, including taurocholic (OR =4.70, 95% CI=2.51-8.78; Q-trend&amp;lt;0.0001), taurochenodeoxycholic (OR =4.61, 95% CI=2.38-8.91; Q-trend&amp;lt;0.0001), and glycocholic acid OR =4.11, 95% CI=2.11-7.99; Q-trend&amp;lt;0.0001), and 11 were positively associated with fatal liver disease risk, including taurochenodeoxycholic acid (OR =9.65, 95% CI=4.41-21.14; Q-trend&amp;lt;0.0001), taurocholic OR =7.45, 95% CI=3.70-14.97; Q-trend&amp;lt;0.0001), taurochenodeoxycholic (OR =9.05, 95% CI=4.04-20.32; Q-trend&amp;lt;0.0001), and glycocholic acid OR=6.12, 95% CI=2.84-13.77; Q-trend&amp;lt;0.0001). No significant associations were observed between BAs and biliary cancer though ORs were consistently &amp;gt;1. Conclusion: Conjugated BAs were strongly associated with increased risk of liver cancer and fatal liver disease, suggesting mechanistic links between the gut microbiota, BA signaling pathways, and liver cancer or death from liver disease. Citation Format: Zeinab Farhat, Neal D. Freedman, Joshua N. Sampson, Roni T. Falk, Jill Koshiol, Stephanie J. Weinstein, Demetrius Albanes, Rashmi Sinha, Erikka Loftfield. A prospective investigation of serum bile acids with risk of liver cancer, fatal liver disease, and biliary cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2385.

Relationship between chocolate consumption and overall and cause-specific mortality, systematic review and updated meta-analysis.

Chocolate is a rich dietary source of various bioactive flavonoid compounds. Despite being one of the most popular foods worldwide, the association between chocolate consumption and long-term mortality remains unclear. The objective of this study is to determine the associations between chocolate consumption and long-term overall and cause-specific mortality, to evaluate dose-response and potential mediators, and to conduct an updated meta-analysis based on prospective cohort studies. We performed a prospective analysis in the Alpha-Tocopherol, Beta-Carotene cancer prevention (ATBC) Study with a total of 27,111 men who were recruited between 1985 and 1988 and followed through 2015. Exposure data of daily chocolate consumption was obtained from validated baseline food frequency questionnaire. Hazard ratios (HRs) and 30-year absolute risk differences (ARDs) including 95% confidence intervals (CI) for overall and cause-specific mortality were estimated using multivariable-adjusted Cox proportional hazards regression models. An updated meta-analysis of cohort studies was also conducted. During 482,807 person-years of follow-up, a total of 22,064 men died. The multivariable analyses showed a statistically significant inverse association between chocolate consumption and risk of overall mortality, with HRs of 0.91, 0.89, 0.89, and 0.88 for the increasing categories 2-5 as compared with those in the lowest category (Ptrend < 0.0001, and P for nonlinearity < 0.0001). We observed significantly lower mortality from cardiovascular disease (CVD), heart disease and cancer, representing 13%, 16% and 12% risk reductions for the highest compared to lowest chocolate category, respectively (all Ptrend ≤ 0.002; all P for nonlinearity < 0.0001). The inverse associations of chocolate consumption with risk of overall, CVD and heart disease mortality were generally consistent across cohort subgroups (e.g., body mass index and serum cholesterol). Mediation analysis showed that 4.3% of the inverse association of chocolate and overall mortality was mediated through reducing blood pressure. Within the updated meta-analysis of cohort studies (21 risk estimates, 908,390 participants and 65,407 events), greater consumption of chocolate (per 5g/day) was associated with a lower risk of CVD incidence and mortality (pooled relative risk = 0.98, P value < 0.001; P for nonlinearity < 0.001). The predefined subgroup analyses generally revealed consistent inverse chocolate-CVD risk associations. In this prospective study, calorie-balanced greater consumption of chocolate was inversely associated with lower overall, CVD, heart disease and cancer mortality. The systematic review and meta-analysis provide support for the inverse chocolate-CVD association. Our findings may provide evidence to partially allay concerns regarding adverse health outcomes from low-to-moderate chocolate consumption.

Prospective Associations of Circulating Bile Acids and Short-Chain Fatty Acids With Incident Colorectal Cancer.

Human studies investigating the prospective relationship between microbial metabolites and colorectal cancer (CRC) risk are lacking. We tested whether higher serum bile acids (BAs) and lower short-chain fatty acids (SCFAs) were associated with CRC risk. In baseline serum collected more than 30 years before a CRC diagnosis, we quantified concentrations of 15 BAs and 6 SCFAs using targeted liquid chromatography with tandem mass spectrometry assays in 1:1 matched cases and controls from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial (men: n = 262 cases; women: n = 233 cases) and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (men: n = 598 cases). We estimated odds ratios (ORs) and 95% confidence intervals (CIs) for BA and SCFA quartiles and summary measures with CRC overall and by anatomic location using multivariable conditional logistic regression models. PLCO analyses were stratified by sex. All statistical tests were 2-sided. In PLCO women, 7 BAs were strongly associated with increased CRC risk, including the secondary BAs, deoxycholic (ORQ4 v Q1 = 2.85, 95% CI = 1.45 to 5.60, Qtrend = 0.011), glycodeoxycholic (OR Q4 v Q1 = 3.45, 95% CI = 1.79 to 6.64, Qtrend = 0.006), taurodeoxycholic (OR Q4 v Q1 = 2.36, 95% CI = 1.22 to 4.55, Qtrend = 0.023), and glycolithocholic acid (ORQ4 v Q1 = 2.71, 95% CI = 1.41 to 5.22, Qtrend = 0.015). Women in the highest compared with lowest quartile of total SCFAs had a 45% lower risk of CRC (OR = 0.55, 95% CI = 0.31 to 0.98, Ptrend = .03). Associations for total BAs and SCFAs were strongest among women with proximal colon cancer. No statistically significant associations were observed for BA or SCFA measures among men. Serum concentrations of BAs, particularly downstream microbial metabolites of cholic acid, were strongly associated with increased risk of CRC among women.

Metabolomic analysis of serum alpha-tocopherol among men in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study.

Background/Objectives:The role of vitamin E in chronic disease risk remains incompletely understood, particularly in an un-supplemented state, and evidence is sparse regarding the biological actions and pathways involved in its influence on health outcomes. Identifying vitamin-E-associated metabolites through agnostic metabolomics analyses can contribute to elucidating the specific associations and disease etiology. This study aims to investigate the association between circulating metabolites and serum α-tocopherol concentration in an un-supplemented state.Subjects/Methods:Metabolomic analysis of 4,294 male participants was conducted based on pre-supplementation fasting serum in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. The associations between 1,791 known metabolites measured by ultra-high-performance LC-MS/GC-MS and HPLC-determined α-tocopherol concentration were estimated using multivariable linear regression. Differences in metabolite levels per unit difference in α-tocopherol concentration were calculated as standardized β-coefficients and standard errors.Results:A total of 252 metabolites were associated with serum α-tocopherol at the Bonferroni-corrected p-value (p<2.79×10−5). Most of these metabolites were of lipid and amino acid origin, with the respective subclasses of dicarboxylic fatty acids, and valine, leucine, and isoleucine metabolism, being highly represented. Among lipids, the strongest signals were observed for linoleoyl-arachidonoyl-glycerol (18:2/20:4)[2](β=0.149; p=8.65×10−146) and sphingomyelin (D18:2/18:1) (β=0.035; p=1.36×10−30). For amino acids, the strongest signals were aminoadipic acid (β=0.021; p=5.01×10−13) and l-leucine (β=0.007; p=1.05×10−12).Conclusions:The large number of metabolites, particularly lipid and amino acid compounds associated with serum α-tocopherol provide leads regarding potential mechanisms through which vitamin E influences human health, including its role in cardiovascular disease and cancer.