MYH gene mutation tied to colorectal cancer

Mutations of the MutY human homologue (MYH) gene, a gene involved in repairing oxidative damage to DNA, appear to be associated with an increased risk of colorectal cancer, US and Canadian researchers report in the November 3rd issue of the Journal of the National Cancer Institute.

“It appears that about 1% of all colorectal cancer cases in North America are caused by biallelic MYH gene mutations and relatives of these cases may be at very increased risk of colorectal polyps and colorectal cancer,” senior author Dr. Steven Gallinger told Reuters Health. Moreover, he added, monoallelic “mutation carriers are probably at increased risk as well, although more work is needed to refine the risk estimate.”Dr. Gallinger of Mount Sinai Hospital, Toronto and colleagues came to these conclusions after studying a series of 1238 colorectal cancer patients and 1255 healthy controls from Ontario. In all, there were 41 MYH mutation carriers among the patients and 21 among the controls.In particular, it was found that compared with noncarriers, those with MYH mutations had an increased risk of colorectal cancer. Moreover, they also had an increased risk (odds ratio 1.54) of having first- or second-degree relatives with colorectal cancer.The investigators call for larger studies, but suggest the findings “be considered in current genetic testing practices and in screening colonoscopy recommendations for individuals at high risk of colorectal cancer.”(Source: J Natl Cancer Inst 2004;96:1631-1634: Reuters Health: David Douglas: Oncolink: November 2004.)