BRCA1 and BRCA2 mutations may be more common in the general population than previously reported and may be associated with ovarian, breast, testicular, and pancreatic cancers, according to a study in the December 6 issue of the Journal of the National Cancer Institute.
Mutations in the BRCA1 and BRCA2 genes are known to lead to breast and ovarian cancer. However, the frequency of these mutations in the general population has not been well-characterized.
Harvey A. Risch, M.D., Ph.D., of the Yale University School of Medicine in New Haven, Conn., and colleagues looked for BRCA1 and BRCA2 mutations in 1,171 ovarian cancer patients from Ontario who were diagnosed between 1995 and 1999. They examined cancer outcomes in the patients' 8,680 first-degree relatives.
The authors found that 13.2% of the ovarian cancer patients had BRCA1 or BRCA2 mutations compared with 0.32% for BRCA1 mutations and 0.69% for BRCA2 mutations in the general Ontario population. BRCA1 mutations in the general Ontario population were associated with higher risk of ovarian, female breast, and testicular cancers. BRCA2 mutations in the general Ontario population were associated with higher risks of male and female breast, ovarian, and pancreatic cancer. They estimated that about 1% of people in the general Ontario population carried these mutations, which is much higher than had been previously thought.
"BRCA1 and BRCA2 mutations should be suspected in families with breast, ovarian, and various other cancers in male relatives as well as female," the authors write.
In an accompanying editorial, Kenneth Offit, M.D., of Memorial Sloan-Kettering Cancer Center, writes that the implications for doctors and patients remain unchanged. The prevalence of BRCA2 mutations associated with ovarian cancer "still warrants consideration of risk-reducing surgery, albeit at a somewhat older age than that recommended for BRCA1 mutation carriers. ...BRCA mutation status remains one of the strongest markers for risk of this disease, warranting increased surveillance with such modalities as magnetic resonance imaging, hormonal and other chemoprevention, and, in selected circumstances, preventive surgery."
Article: Risch HA, McLaughlin JR, Cole DEC, Rosen B, Bradley L, Fan I, Tang J, Li S, Zhang S, Shaw PA, Narod SA. Population BRCA1 and BRCA2 Mutation Frequencies and Cancer Penetrances: A Kin-Cohort Study in Ontario, Canada, J Natl Cancer Inst 2006; 98:1694-1706
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