Women with a strong family history of breast cancer but no BRCA mutation do not have increased risk for ovarian cancer, according to an article in the September 21 issue of the Journal of the National Cancer Institute.

The current work is one of the first prospective studies to allow doctors to tailor ovarian cancer screening recommendations for women with a family history of breast cancer but with no identifiable BRCA mutation.

In the ten years since the discovery of BRCA1 and BRCA2 genes, it has been learned that the risk for ovarian cancer in families with mutations in these genes is increased 6-fold to 61-fold. However, it has also emerged that up to half of families with multiple cases of breast cancer do not have mutations in either BRCA1 or BRCA2. Until the current study, there have been only limited data with which to inform such families on risk for ovarian cancer.

The Memorial Sloane Kettering Clinical Genetics Service studied 199 families with multiple cases of breast cancer but no identified BRCA mutation. During follow-up, 19 new cases of breast cancer were diagnosed ? three times more than the six cases that were expected. Only one case of ovarian cancer was diagnosed, which is what researchers would have anticipated in an average risk population.

While the authors conclude that women from these families do not have an increased risk of ovarian cancer, they also indicate that the genetic mechanism for up to half of hereditary breast cancer cases remains unknown. Research is ongoing to map undiscovered genes associated with hereditary breast cancer.