Specific genes highlighted for alcohol cancer risk

Variants in certain genes lower the risk of various types of cancers in individuals who consume alcohol, reports a study published online this week in Nature Genetics. The genes, which encode enzymes that metabolise alcohol, reduce cancers of the mouth, larynx, pharynx and oesophagus.

Alcohol consumption is a risk factor for cancers of the upper aerodigestive tract, and some published evidence supports the notion that variation in the enzymes that metabolise alcohol - alcohol dehydrogenases (ADH) - might influence cancer susceptibility.

Paul Brennan and colleagues genotyped 6 ADH variants in more than 3,800 individuals with aerodigestive cancer and over 5,200 controls. One variant each in ADH1B and ADH7 were significantly protective against aerodigestive cancer specifically in individuals who were alcohol drinkers, and most strongly in those who had higher alcohol intake. Individuals with the protective variant in ADH1B are known to metabolise alcohol up to 100 times faster than those without it, suggesting that lower exposure to alcohol is protective against the disease.

‘It has been known for some considerable time that alcohol drinking is a risk factor for cancer although its importance has been underestimated" said Dr Peter Boyle, Director of the International Agency for Research on Cancer. "These findings contribute considerably to the understanding of the mechanism of action of alcohol as a carcinogen.'

'The results also highlighted the role of alcohol in causing these cancers as the genes had no effect among people who did not drink alcohol, and became more important with higher levels of alcohol consumption', said Dr Brennan.