A genetic discovery could help explain why some people who drink too much develop cancers, while others do not. A European study, published in Nature Genetics, has found two gene variants which offer “significant” protection against mouth and throat cancers. It suggested that people who have them are much better at breaking down alcohol into less harmful chemicals.
Cancer Research UK said cutting down on the amount you drink is the best way to prevent cancer. More than seven out of ten people diagnosed with mouth cancers drink far more than the recommended sensible drinking guidelines of 2 3 units a day for women and 3-4 for men - and, alongside smoking, it is also a known risk factor for oesophageal cancer.
Previous research had identified a group of genes called ADH as clear candidates for a role in the development of these cancers. These genes make body chemicals which help break down alcohol, and, in theory, the more effective these are, the less opportunity alcohol has to damage the cells in the mouth and throat.
Led by the International Agency for Research on Cancer in Lyon, France, the research team spent five years studying 3,800 patients with oral cancers and cancers of the larynx and oesophagus, and 5,200 who were free of the disease at 23 centres throughout Europe and Central and South America.
The study discovered that people’s risk of developing cancers of the mouth, larynx, pharynx and oesophagus is related to genes which regulate how fast or slow your body breaks down alcohol.
They found two variants in the group of ADH genes were linked to a lower chance of getting cancer. Looking only at study participants who admitted drinking heavily, the potentially beneficial effect of having one of the variants was even more pronounced, in line with the amount of alcohol consumed.
Dr Tatiana Macfarlane, Senior Lecturer in Medical Statistics at the University of Aberdeen’s Department of General Practice and Primary Care, was involved in the study which took place while she was at the University of Manchester.
She said: “The study showed that your risk of getting oral cancers is linked to genetics as well as lifestyle. We found that, in particular, the risk depends on how fast your body metabolises alcohol. The results suggest that the faster you metabolise it, the lower your risk...These results provide the strongest evidence yet that high alcohol consumption is strongly linked to oral cancers. The risk is particularly high if you also smoke or rarely eat fruit and vegetables.”
Source: ‘Multiple ADH genes are associated with upper aerodigestive cancers. Nature Genetics 40, 707 - 709 (01 Jun 2008), doi: 10.1038/ng.151, Brief Communications