Novel Biomarkers of Habitual Alcohol Intake and Associations with Risk of Pancreatic and Liver Cancers and Liver Disease Mortality.

BACKGROUND Alcohol is an established risk factor for several cancers, but modest alcohol-cancer associations may be missed due to measurement error in self-reported assessments. Biomarkers of habitual alcohol intake may provide novel insight into the relationship between alcohol and cancer risk. METHODS Untargeted metabolomics was used to identify metabolites correlated with self-reported habitual alcohol intake in a discovery dataset from the European Prospective Investigation into Cancer and Nutrition (EPIC; n = 454). Statistically significant correlations were tested in independent datasets of controls from case-control studies nested within EPIC (n = 280) and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC; n = 438) study. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations of alcohol-associated metabolites and self-reported alcohol intake with risk of pancreatic cancer, hepatocellular carcinoma (HCC), liver cancer, and liver disease mortality in the contributing studies. RESULTS Two metabolites displayed a dose-response association with self-reported alcohol intake 2-hydroxy-3-methylbutyric acid and an unidentified compound. A 1-SD (log2) increase in levels of 2-hydroxy-3-methylbutyric acid was associated with risk of HCC (OR = 2.54; 95% CI = 1.51-4.27) and pancreatic cancer (OR = 1.43; 95% CI = 1.03-1.99) in EPIC and liver cancer (OR = 2.00; 95% CI = 1.44-2.77) and liver disease mortality (OR = 2.16; 95% CI = 1.63-2.86) in ATBC. Conversely, a 1-SD (log2) increase in questionnaire-derived alcohol intake was not associated with HCC or pancreatic cancer in EPIC or liver cancer in ATBC but was associated with liver disease mortality (OR = 2.19; 95% CI = 1.60-2.98) in ATBC. CONCLUSIONS 2-Hydroxy-3-methylbutyric acid is a candidate biomarker of habitual alcohol intake that may advance the study of alcohol and cancer risk in population-based studies.