Familial Breast Cancer Gene Linked to Some Other Cases : SCIENCE FILE / An exploration of issues and trends affecting science, medicine and the environment

A defect in a familial breast cancer gene discovered in 1994 also appears to cause a significant share of sporadic, non-familial breast cancer cases in young women, according to researchers at Massachusetts General Hospital in Boston and the Fred Hutchinson Cancer Research Center in Seattle. The gene appears to be especially active in Jews, in whom it may trigger more than a quarter of all cases detected before age 40.

The gene, called BRCA1, was known to cause about half of all cases of inherited breast cancer. Now, two new studies reported in the Jan. 18 edition of the New England Journal of Medicine show for the first time that the same gene is frequently the cause whenever the disease strikes women in their 20s and 30s, even if there is no strong pattern of breast cancer among the victim’s close relatives.