Many people of East Asian descent possess an enzyme deficiency that causes their skin to redden, or flush, when they drink alcohol.
Scientists from the National Institute on Alcohol Abuse and Alcoholism (NIAAA) and Japan's Kurihama Alcohol Center now caution that heavy alcohol consumption greatly increases the risk for esophageal cancer among such individuals, who comprise about 8 percent of the world's population. Their review of recent research on this topic appears in the March 24, 2009 issue of PLoS Medicine. NIAAA is part of the National Institutes of Health.
"It is very important for clinicians who treat patients of East Asian descent to be aware of the risk of esophageal cancer from alcohol consumption in their patients who exhibit the alcohol flushing response, so they can counsel them about limiting their drinking," says NIAAA Acting Director Kenneth R. Warren, Ph.D.
First author Philip J. Brooks, Ph.D., of NIAAA's Laboratory of Neurogenetics, and his colleagues note that a clinician can reliably determine whether a patient is at risk simply by asking about previous episodes of facial flushing after drinking alcohol. Considered from this perspective, the authors point out, the flushing response is a clinically useful biomarker of genetic susceptibility to esophageal cancer risk from alcohol.
Dr. Brooks cites the high mortality from esophageal cancer and the large number of individuals with the deficient enzyme, known as aldehyde dehydrogenase 2 (ALDH2).
"Cancer of the esophagus is particularly deadly, with five-year survival rates ranging from 12 to 31 percent throughout the world. And we estimate that at least 540 million people have this alcohol-related increased risk for esophageal cancer," he notes. "We hope that, by raising awareness of this important public health problem, affected individuals who drink will reduce their cancer risk by limiting their alcohol consumption."
Dr. Brooks and his colleagues explain that ALDH2 plays an important role in alcohol metabolism. When alcohol is consumed, it is first metabolized into acetaldehyde, a chemical similar to formaldehyde, which causes DNA damage and has other cancer-promoting effects. ALDH2 is the main enzyme responsible for breaking down acetaldehyde into acetate, a non-toxic metabolite in the body.