New Breast Cancer Risk Pinpointed for Women With Genetic Variant

Aug 07, 2014 12:00 am ET

Aug. 7 (Bloomberg) -- Scientists have filled in another piece of the breast cancer puzzle with a finding that a mutated gene responsible for DNA repair raises the risk for women who carry it, suggesting it should be included in early testing.

Those with the PALB2 mutation have a 33-to-58 percent chance of developing breast cancer by age 70, depending on their family history, according to the research published in the New England Journal of Medicine.

More than 232,000 U.S. women will be diagnosed with breast cancer this year and 40,000 will die, according to the U.S. National Cancer Institute. The PALB2 mutation occurs in about 2.4 percent of women with a family history of the disease, according to the researchers.

“This particular mutation doesn’t make people certain to develop cancer, but it’s another piece of information to help women make proper informed choices about how they may help to minimize their own risk,” said Peter Johnson, chief clinician at Cancer Research U.K., which helped fund the study.

PALB2 was initially linked to breast cancer in 2007. The study provides the first estimate of the risk tied to the mutation, which is known to interact with the breast tumor genes BRCA1 and BRCA2.

362 Included

The study included 362 family members with PALB2 mutations. It showed that women with the mutation with no family history of cancer had a 33 percent chance of developing the malignancy by age of 70. Those with the mutation and a strong family history had a 58 percent risk.

Women with the BRCA1 and BRCA2 mutations carry between a 50 percent and 80 percent lifetime risk of developing breast cancer on average, according to Marc Tischkowitz, a study leader and an associate professor in the Department of Medical Genetics at the University of Cambridge in the U.K.

“It’s another piece of the jigsaw,” Tischkowitz said in a telephone interview. Those who also carry the PALB2 mutation should have additional MRI surveillance to help catch the disease early, he said.

Influencing Chance

“We’re learning all the time about the different factors that may influence a woman’s chance of developing breast cancer,” said Cancer Research’s Johnson.

New drugs in development called PARP inhibitors may benefit patients with PALB2 mutations, researchers said.

Companies including AstraZeneca Plc, Abbvie Inc., BioMarin Pharmaceutical Inc., Clovis Oncology Inc. and Tesaro Inc. are developing the new class of treatments, designed to prevent cancer cells from repairing themselves after chemotherapy. Some of the drugs are being tested in patients with BRCA1 and BRCA2- related breast cancers.