Gene Affects Aspirin Prevention of Colorectal Adenomas
Researchers find lower risk in aspirin takers with ornithine decarboxylase (ODC) gene variations
THURSDAY, Oct. 19 (HealthDay News) -- Aspirin therapy may help reduce the risk of colorectal adenomas in patients with certain ornithine decarboxylase (ODC) gene polymorphisms, but not in patients without that particular genotype, according to a study in the Oct. 18 issue of the Journal of the National Cancer Institute.
Elizabeth L. R. Barry, Ph.D., of Dartmouth Medical School in Lebanon, N.H., and colleagues analyzed ODC genotype in 973 subjects at high risk of developing adenomas, randomly assigned them to either daily aspirin or placebo, and followed them for three years.
The researchers identified 54 percent of subjects as homozygous wild-type (GG), 7 percent as homozygous variant (AA), and 39 percent as heterozygous. In GG subjects, they found that aspirin had no protective effect. But in subjects with at least one A allele, aspirin significantly reduced the risks of any adenoma (relative risk, 0.77) and of advanced lesions (RR, 0.51).
"Our findings do suggest that ODC genotype may be an important predictor of the response to aspirin use for adenoma chemoprevention," the authors conclude. "Future studies should examine the association between ODC genotype and colorectal cancer (rather than adenoma occurrence). Due to the very small numbers of ODC AA homozygotes, larger numbers of subjects would be required to address these hypotheses with sufficient power."