Link of Heavy Drinking, Genetic Variant, and Gastric Cancer Confirmed
Orlando, FL—Heavy beer drinkers who have a genetic variant related to alcohol metabolism are at significantly increased risk of developing gastric cancer, researchers said at the 2011 American Association for Cancer Research meeting.
Heavy beer drinking raised the gastric cancer risk regardless of the presence of the genetic variant, but not as significantly as in the presence of the variant, reported Eric Duell, PhD, Senior Epidemiologist in the Cancer Epidemiology Research Program at the Catalan Institute of Oncology in Barcelona, Spain.
The variant, known as rs1230025, is part of the alcohol dehydrogenase gene cluster (ADH1) that produces an enzyme that breaks down alcohol. The investigators postulated that this variant might predispose heavy beer drinkers to an increased risk for gastric cancer.
Alcohol use has long been suspected to be a contributing factor for gastric cancer, but numerous studies have yielded mixed results. This is the first time an association has been found among beer drinking, genetic variants, and gastric cancer.
“This is a classic gene-environment interaction,” Dr Duell suggested. “Having both of these risks—heavy beer consumption and rs1230025— appears to be worse in terms of gastric cancer risk than having just one or neither.”
The researchers analyzed alcohol consumption and gastric cancer risk in more than 521,000 persons (aged 35-70 years) participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study from 1992 through 1998.
In a case-control substudy of 365 gastric cancer cases and 1284 controls within EPIC, 2 single-nucleotide polymorphisms (SNPs) in the gene cluster ADH1 showed significant association with gastric cancer risk—rs283411 and rs1230025. One of these, rs1230025, interacted with beer consumption to further increase the risk, Dr Duell said.
Compared with low ethanol consumption at baseline (0.1-4.9 g/day), heavy total alcohol (≥60 g/day) and beer consumption (≥30 g/day) were significantly associated with increased risk for gastric cancer. The overall increased risk with alcohol was 65%, and 75% with beer drinking. One 12-ounce beer contains approximately 13 g of pure ethanol/alcohol.
“When we looked at these 2 factors together—heavy beer drinking and having 2 copies of the variant—people had more than a 700% increased risk of gastric cancer,” Dr Duell said at a press briefing. “The results need to be replicated in other populations, as this is the first study to show a relationship between this SNP and gastric cancer risk.”
The exact mechanism for how alcohol may cause gastric cancer is not known, although the metabolite of alcohol, acetaldehyde, is a toxic and carcinogenic compound. Nitrosa – mines, which are found in beer, are a known animal carcinogen, Dr Duell pointed out.