BRCA mutations not linked to colon cancer risk

Founder mutations in BRCA1 and BRCA2 have been linked to breast and ovarian cancer, but they do not seem to increase the risk of colorectal cancer, according to two reports published in the January 7th issue of the Journal of the National Cancer Institute.

In one study, Dr. Kenneth Offit and colleagues, from Memorial Sloan-Kettering Cancer Center in New York, looked at the frequency of such mutations in an unselected group of 586 Ashkenazi Jewish patients with colorectal cancer. The incidence of mutation carriers in this group was compared with that seen in 5012 control subjects without cancer. The presence of a founder mutation was not significantly tied to the risk of colorectal cancer, the researchers found. In a similar study, Dr. Stephen B. Gruber, from the University of Michigan at Ann Arbor, and colleagues investigated the rate of BRCA founder mutations in a northern Israel population. The study included 1422 patients with colorectal cancer and 1566 control subjects.The incidence of mutation carriers in the cancer group was 2.4%, not significantly higher than the rate in the control group — 1.9% — the investigators note. Moreover, even after adjusting for the presence of a BRCA mutation, having a female family member with breast cancer did not raise the risk of colon cancer in the index subject.Coupled with past reports, the current findings suggest that “for most individuals at increased risk of breast cancer, including those with the common breast/ovarian cancer founder mutations, colorectal cancer is at least one issue that they don’t have to worry so much about,” Dr. Judy E. Garber and Dr. Sapna Syngal, from Dana-Farber Cancer Institute in Boston, note in a related editorial.(Source: J Natl Cancer Inst 2004;96:2-3,15-21,68-70: Reuters Health: January 7, 2004: Oncolink)