Chicago-based medical oncologist and cancer researcher Dr. David James VanderWeele answers your questions about BRCA gene mutations in men.
Q:My sister recently tested positive for the BRCA1 gene mutation, and her genetic counselor saidr the rest of her family members should get tested, too. But I’m a man. I thought BRCA was about breast cancer? Is there any reason why men should also be concerned about BRCA?
We are learning more and more about BRCA1 and 2 mutations. Obviously we associate them more with breast and ovarian cancer, but we in the prostate cancer community have realized that it has strong implications for other cancers, too. Patients who inherit a mutation in BRCA1 or 2 from their parents also have a mutation in the cells in their body. They’re more likely to develop prostate cancer, just like their female relatives may be more likely to develop breast or ovarian cancer. That’s especially true for a BRCA2 gene mutation. They’re also more likely to develop a more aggressive form of prostate cancer.
Q:Unfortunately, breast and prostate cancer seem to run in my family. There is a strong possibility we have an inherited BRCA gene mutation. What should I do?
For someone who is not diagnosed with prostate cancer but they have a family history of prostate, breast, ovarian, or maybe even pancreatic cancer, the first step is asking a family member who has one of those cancers to undergo germline testing. If the testing identifies a mutation that runs in the family, other family members can look for that specific mutation a little more easily.
If a family member tests positive, this should lead to cascade testing. With cascade testing, additional family members will also get tested sequentially. For instance, if an aunt or an uncle is the family member to undergo initial testing, their siblings would be the next ones to get tested. If those siblings test negative, then all of their children are presumed to be negative, but if they test positive, then their children still have a 50 percent chance of having the gene mutation.
Talk to a genetic counselor to think through all the implications of the testing, both for yourself and other family members. Your genetic counselor can let you know if it makes sense for you to get tested given your family history.
Check to see if your insurance will pay for genetic testing. If not, there are other testing panels that are relatively affordable out of pocket compared to testing in the past. For someone who has a known germline mutation or suspect they might, we are still trying to figure out the best way to do screening. For prostate cancer, you may consider getting a screening for prostate cancer through PSA testing.
Q:What if I don’t test positive for a BRCA gene mutation. Are there any other hereditary cancer syndromes I should be aware of?
There are. There is a prostate cancer syndrome that seems to be linked only to prostate cancer and not other cancers, that we know of. There’s the strongest data for this in northern Europeans in a gene called HOXB13. It’s not clear if it’s very common in other populations. If you were going in for a testing panel that would include BRCA1 and 2, they likely would not include testing for HOXB13. At the moment, HOXB13 is only linked to prostate cancer and would probably have to be looked at specifically on it’s own.
In addition, prostate cancers may also be more frequent in patients with lynch syndrome, which is what we associate with colorectal cancer or endometrial cancer. This syndrome likely leads to an increased risk of other cancers as well.
About the Doctor
Dr. David James VanderWeele is a medical oncologist and clinical researcher at Northwestern University’s Robert H. Lurie Comprehensive Cancer Center. He received his medical and research training at the University of Chicago before moving to the National Cancer Institute where he sought to improve the treatment of prostate cancer based on a patient’s genetics.