The Philadelphia Inquirer writes there are other, lesser-known risk genes for breast cancer beyond the BRCA genes.
"BRCA1 and BRCA2 are the tip of the iceberg," Penn Medicine's Angela Bradbury tells the paper. "There are many other mutations."
One such risk gene is PALB2, which normally acts as a DNA repair gene, but people who harbor risk variants in it have a 14 percent risk of developing breast cancer by age 50, while the general population has a lifetime risk of breast cancer of about 12 percent, the Inquirer says. It notes that mutations in the BRCA genes confer even higher risks.
A Philadelphia-area family carries a mutation in this gene: Tracy Brown has been diagnosed with ductal carcinoma in situ, while her sister has Stage 2A breast cancer and her mother has thyroid cancer, according to the Inquirer. Other relatives have also had cancer, though before gene testing was available.
Because of her family history, Brown sought a radical treatment. "With the double mastectomy and the early-stage cancer, I don't have the fears that my sister had to live with," she tells the Inquirer. "I'm in a place where there's a 95 to 99 percent chance the cancer might not come back."