Breast, prostate cancers cluster in families
There's more evidence suggesting that women are more likely to develop breast cancer in prostate cancer runs in their immediate family. Their findings from the Women's Health Initiative reinforce suggest that since breast and prostate cancers tend to cluster in families, the two conditions share common genes.
More than 78,000 cancer-free women over the age of 50 were analyzed for the study, which began in 1993. The majority of the women participated for more than 10 years. At the start, women underwent a physical exam and detailed family and person histories were recorded. By 2009, 3,506 new breast cancer cases were diagnosed within the study group.
Of the participants, more than 11,000 had a mother, sister or daughter with breast cancer—this stat was more common for those who would eventually be diagnosed with the disease themselves—and 20 percent had a first-degree relative with breast cancer.
But more than 11 percent who went on to develop breast cancer had reported a first-degree relative with prostate cancer. Those with a father, brother or son with prostate cancer increased their risk of developing breast cancer by about 14 percent, according to the research. Compared to people who had no family history of either breast or prostate cancer, those who had a family history of both cancers were 80 percent more likely to develop breast cancer.
Researchers believe the possible link lies within the breast cancer genes BRCA1 and BRCA2 genes, which have been associated with prostate cancer as well.