Did you know that you can inherit prostate cancer from your mother?

You can — if you inherited a defective DNA repair gene. When working correctly, these genes are an important defense force in the body, repairing the damage to DNA caused by solar radiation, food and pollution.

“Your cells are exposed to DNA-damaging sources every day,” explains oncologist Bruce Montgomery, M.D. “But when you already have damage to a gene that repairs DNA, your likelihood of getting more damage goes up astronomically.” And this damage is the first step on the path to cancer.

When Montgomery sequenced the genomes of men with metastatic prostate cancer as part of a large international study, something became immediately apparent. “Close to 30 percent of these men had a defective DNA repair gene. And almost half of those men, around 12 percent, had inherited this defect from either their mother or their father,” he says.

In short: You can get prostate cancer if your mother has a defective DNA repair gene. Conversely, you can get ovarian cancer or breast cancer if your dad has the same defect.

“Women tend to look only at their maternal family history when assessing their own risk for breast cancer. But these mutations can be inherited just as easily from your mom or your dad,” says breast and ovarian cancer expert Liz Swisher, M.D., Res. ’93.

It’s a family problem, for sure. If a person has one of these DNA repair defects, everyone related to them has a 50-50 chance of also being a carrier. “There is a cascade of people who need to be tested,” says Montgomery.

Swisher is testing women at risk of developing ovarian and breast cancer through a study called the MAGENTA (Making Genetic Testing Accessible) study. Montgomery is using the GENTLeMEN (Genetic Testing for Men With Prostate Cancer) study to assess whether men with metastatic prostate cancer have DNA repair deficiencies. In both these studies, knowledge becomes power for patients and their families — in part because there are therapies that have been proven effective at treating cancer caused by this type of deficiency.

Prostate cancer survivor Loch Anderson and his wife, Allyn Perkins, have made a donation to the GENTLeMEN study. They believe in the science, and they hope for something more: that the study will spur conversation.

“One of the frustrating things about prostate cancer is that men don’t talk about it,” Anderson says. “Part of the GENTLeMEN study is getting it out in the open, making it no different than breast cancer. The more people talk about it, the more proactive they will be in their own care.”

Illustrations: David Hoyt