In two large studies, the association between aspirin use and risk of colorectal cancer was affected by mutation of the gene BRAF, with regular aspirin use associated with a lower risk of BRAF–wild-type (the typical form of a gene as it occurs in nature) colorectal cancer but not with risk of BRAF-mutated cancer. These findings that suggest that BRAF-mutant colon tumor cells may be less sensitive to the effect of aspirin, according to a study in the June 26, 2013, issue of JAMA.
Reiko Nishihara, PhD, of the Dana-Farber Cancer Institute, Boston, and colleagues collected biennial questionnaire data on aspirin use and followed up participants in the Nurses’ Health Study (from 1980) and the Health Professionals Follow-up Study (from 1986) until July 2006 for cancer incidence and until January 2012 for cancer mortality.
Among 127,865 individuals, 1,226 incident rectal and colon cancers were identified with available molecular data. The researchers found that regular aspirin use was associated with a significantly lower risk (27%) of BRAF–wild-type cancer. Regular aspirin use was not associated with a lower risk of BRAF-mutated cancer.