Everyone has two PALB2 genes, one from their mother and one from their father. When the genes work properly, they make a protein that works with another gene to repair damaged DNA and stop tumor growth.
But sometimes people inherit a mutated gene. When PALB2 is mutated, it can’t suppress tumor growth, increasing a person’s risk for getting cancer in certain parts of their body, including breasts, ovaries, pancreas and prostate, said Sara Rhode, a genetic counselor at the Cleveland Clinic Maroone Cancer Center in Weston.
Doctors knew PALB2, when mutated, could increase a person’s risk for certain types of cancer. But recent research has shown that women with mutated PALB2 genes are at risk for breast cancer nearly as much as those who have the more well-known BRCA genetic mutations, said Dr. Cassann Blake, a breast oncology surgeon at Cleveland Clinic’s Weston location.
This makes PALB2 the “third most important breast cancer gene after BRCA1 and BRCA2,” according to the American College of Medical Genetics and Genomics.
Genetic testing is how mutated genes are identified, and while it can be helpful in determining a woman’s risk for breast cancer, not every woman needs to be tested, according to the American Cancer Society.
Doctors usually have patients undergo a health assessment, which looks at a variety of factors, including the woman’s personal and family history of cancer, to determine if testing is needed.
However, clinical testing of PALB2 hasn’t been available for as long as genetic testing of BRCA1 and BRCA2, so it’s likely that patients who were tested prior to 2013 didn’t have their PALB2 analyzed, according to Yale’s School of Medicine.
“So now, what we’re doing is, those patients that met criteria for genetic testing in the past, we’re bringing them back to retest with what we call expanded genetic testing,” said Dr. Alejandra Perez, a breast medical oncologist with Sylvester Comprehensive Cancer Center at the University of Miami.