Genetic Clues to Cancer Risk From GERD
Researchers Use Genetic Markers to Identify GERD Patients at Risk for Esophageal Cancer
Jan. 13, 2009 -- Researchers say they are a step closer to developing a genetic test to predict which people with acid reflux will develop esophageal cancer.
Nearly 20 million people in the U.S. suffer from gastroesophageal reflux disease, or GERD, and doctors have known for some time that it is a risk factor for esophageal cancer.
Yet only a small fraction of people with GERD develop esophageal cancer, and "the question is, why?" says Winson Y. Cheung, MD, a clinical research fellow working with the University of Toronto and the Harvard School of Public Health.
The new study is the first to identify specific genetic markers that are linked with increased cancer risk in people with GERD, he tells WebMD.
The research is being presented this week at the 2009 Gastrointestinal Cancers Symposium in San Francisco. The meeting is cosponsored by the American Society of Clinical Oncology (ASCO) and three other major cancer organizations.
Last year, more than 16,000 Americans were diagnosed with cancer of the esophagus, the tube that carries food from the mouth to the stomach. Nearly 14,000 people died of the disease.
If detected early, the cancer is more curable, but because screening is expensive and invasive (involving the insertion of an endoscope into the esophagus), it is not recommended for all patients with GERD.
Jennifer C. Obel, MD, says that the findings are a step toward identifying which patients are at highest risk of esophageal cancer and would benefit from more aggressive screening. Obel, a gastrointestinal cancers specialist at NorthShore University HealthSystem in Illinois, moderated a discussion of the findings.
Gene Variant Linked to Increased Esophageal Cancer Risk
For the study, Cheung and colleagues collected DNA samples from 309 people being treated for esophageal cancer and 275 healthy people without cancer.
People who had a mutated variant in the epidermal growth factor (EGF) gene and experienced symptoms of acid reflux more than once a month were nearly 10 times more likely to have esophageal cancer, compared with those who had the normal EGF variant and did not have GERD.
Esophageal cancer was increased more than 20-fold among people with the mutation who suffered GERD symptoms more than once a week or for more than 15 years.
Both Cheung and Obel stress that the findings need to be confirmed in larger numbers of people.