"Incidence of esophageal cancer has increased six-fold in the past three decades, and the survival rate is poor," Wu said. "MicroRNAs are exciting because they can modulate the expression of so many human genes."
Major risk factors for esophageal cancer include tobacco smoking, alcohol consumption and reflux disease. The high prevalence of these risk factors in the general population and rare occurrence of this disease provide a clue that genetic predisposition to the disease may play an important role.
Researchers recruited 346 people who were newly diagnosed with esophageal cancer at M. D. Anderson and matched them by age, gender and ethnicity to 346 people without cancer. Only results for Caucasians were reported because of the low numbers of other races that enrolled.
While patients tended to be current smokers and have higher body mass index (BMI), there was no difference between the two groups in alcohol consumption.
One of the most notable findings was a SNP in the mir423 region, which was associated with a significantly lower esophageal cancer risk. The protective effect was significant for smokers and nonsmokers 64 years old and younger, but not for older subjects.
Mir423 also is found in leukemia cells and is altered significantly in other diseases including heart disease and Alzheimer's disease.
Future large-scale, multi-center studies are necessary to confirm these findings, Wu said.
"Our ultimate goal is to construct a comprehensive risk prediction model that includes not only genetic factors, but epidemiological and clinical variables as well, in hopes of predicting the probability of developing esophageal cancer in general population," she said.
|Contact: Robin Davidson|
University of Texas M. D. Anderson Cancer Center