Page last updated: Wednesday, November 19, 2008
Smokers and Drinkers Show Gene Changes in Mouth Cells
Many healthy people who smoke or drink may have a genetic alteration in the cells of the mouth and throat that could signal an increased risk of developing cancer, according to researchers at the University of Hong Kong.

The genetic alteration affects the p15 gene, which is involved in the process that normally kills off cells when they go haywire. In many cancers, the p15 gene is methylated, meaning that it is turned off and is unable to perform its “tumor suppressor” function.

The researchers’ study of healthy adults and patients with head and neck cancers found that 68 percent of healthy smokers and drinkers showed methylated p15 in some of their oral cells. The same was true of 48 percent of the cancer patients, but only 8 percent of healthy adults who were non-smokers and drank only occasionally or not at all.

The investigators say it is unclear whether the healthy men and women who showed signs of p15 methylation are in fact at increased risk of developing head and neck cancer, a group of diseases that includes cancers of the mouth, nasal cavity and throat.

However, the findings do support the idea that “these p15 methylation changes are present in the very early stages of head and neck cancer development,” study co-author Dr. Anthony Po-Wing Yuen told Reuters Health.

That smokers and drinkers face a risk of head and neck cancers is nothing new. Tobacco use is behind the majority of these cancers, and people who smoke and drink are at greater risk than those who do one or the other.

Identifying the “early genetic aberrations” that spur the cancer process may help doctors predict which smokers and drinkers are at particular risk of head and neck cancers, according to Yuen. What’s more, he said, if scientists know which early genetic changes are at the root of cancer, they may be able to develop drugs that reverse these alterations.

However, the researcher stressed, cancer development is a complex process, and a range of factors, including any number of genetic aberrations, conspire to determine who develops cancers of the head and neck.

Source: Chang HW et al. Smoking and drinking can induce p15 methylation in the upper aerodigestive tract of healthy individuals and patients with head and neck squamous cell carcinoma. Cancer 2004;101:125-32.

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