Rise in Risk With New Breast Cancer Gene: Study
One in three women with PALB2 mutation will develop disease by age 70
"It's not common, but the risks are significant," Foulkes said. "Particularly for a woman with a strong family history of breast cancer, they may want to find out if they have this mutation."
Genetic tests for breast cancer already include PALB2 in their panel, Foulkes added.
"In the past few years, it's become easier to test for a package of genes at once," he said. "Women who have had a genetic test should go back and check their records. They may have been tested for PALB2 already and not even know it."
The new PALB2 study involved an international team of researchers from 17 centers in eight countries, led by the University of Cambridge. The scientists analyzed data from 362 family members with PALB2 gene mutations from 154 families without BRCA1 or BRCA2 mutations.
Women who carried rare mutations in PALB2 were found to have, on average, a 33 percent chance of developing breast cancer by age 70.
BRCA1, BRCA2 and PALB2 all play an important role in the repair of damaged DNA. "PALB2 interacts with BRCA2, and acts as a kind of a bridge between BRCA1 and BRCA2," Foulkes explained. Mutation of any of the genes impairs the body's ability to fix broken DNA, which can lead to cancer.
In a separate study also published in the same issue of the NEJM, doctors identified another gene called MEN1 that is linked to breast cancer.
Mutations of the MEN1 gene can cause a rare inherited cancer of the endocrine glands called multiple endocrine neoplasia, but up to now the gene has not been associated with breast cancer.
Researchers found that women with the disease had more than double the risk of also developing breast cancer.
"If you have multiple endocrine neoplasia, then perhaps more intense breast surveillance may be warranted," Foulkes said. "But because it's so rare, you wouldn't say to a woman with a family history of breast cancer, it's probably due to MEN1. It's important for people who have multiple endocrine neoplasia, but probably not for everyone with a family history of breast cancer."