"What do you know about BRCA?" my mother asked. I was home from college for winter break, and we were making dinner. My mother is a lawyer, and not very scientifically inclined. As the only chemistry major of the family, I am the go-to person for all things biomedical. But I didn't know that much about BRCA beyond what I had seen in the media after Angelina Jolie underwent a double mastectomy in 2013. Jolie had a mutant gene that, if present in your genome, dramatically increases the risk of developing breast cancer at a relatively young age.
Since then, I have learned a lot. BRCA 1 and BRCA 2 genes code for tumor-suppressing proteins, the ones that fix DNA damage so cells don't divide like crazy and become a tumor. Specific inherited mutations in these genes are linked to breast and ovarian cancers in women. Carrying one of these gives a woman a significantly increased chance of developing cancer. Between 60 and 85 percent of women with a BRCA mutation develop breast cancer, compared to a 12 percent rate in the general population. Offspring of BRCA mutation carriers have a 50 percent chance of inheriting the mutation.
BRCA mutations can be traced by looking at family histories. In my own family, my mother's half-sister was recently diagnosed with stage 3 ovarian cancer. As she spoke with her doctors about her treatment options, they uncovered a family history of cancer. My aunt also tested positive for a harmful BRCA mutation. Soon after that, my mother's cousin wrote to her, saying that several years ago, she tested positive for BRCA mutations, and chose a prophylactic mastectomy.
My mother and her sisters were understandably furious. They could not believe their cousin had known about the presence of this harmful gene in our family, and had not informed her cousins, all in their fifties and watching carefully for signs of cancer. My mother consulted a genetic counselor. She told her brothers to be tested for the gene, as they might be carriers. While my mother's test is still at the lab, we've already discussed what she would do if she receives a positive result. She had a hysterectomy several years ago, for unrelated reasons, and is willing to have an oophorectomy. She would like to avoid a mastectomy, but will have mammograms every six months instead of every year.
My mother's treatment plan is straightforward. Since her childbearing years are behind her, the game plan is to aggressively screen for abnormal growths in the hopes of detecting any cancer early. For my sister and me, both in our twenties, the decisions are more complicated. Should we be tested?What will we do if we get a positive result? We might want to preserve our fertility until we have a chance to have children, but every year we delay carries an increased risk of cancer. Would we want to avoid having biological children so as not to pass the gene on? If we are carriers, we will face many difficult decisions.
When it comes to genetically inherited diseases and genetic testing, the core question is, "Do you really want to know?" In the case of BRCA, I would argue yes. Cancer is generally most survivable if caught early, and an increased frequency of screenings could be lifesaving. But every individual considering genetic testing will have to confront many questions, including ones about reproductive choice. If a woman has not yet had children, should she avoid passing on the BRCA gene? Many would argue that is too extreme, as cancer is treatable.
But there is also a less obvious question: whom to tell. From a medical standpoint, it might seem irresponsible that my mother's cousin did not tell the extended family about her positive BRCA test. But my mother's extended family is not exactly close-knit. My mother doesn't see her cousin regularly, and besides, choosing a preventative mastectomy is a very personal decision. It's not commonplace to share intimate medical decisions with extended family you don't see regularly.
But the hereditary aspect of gene mutations puts a different light on the issue. My mother and her sisters feel that had their cousin had told them about her BRCA gene, my aunt's cancer might have been caught earlier, and they are probably right. The family has scattered, and little is known about the medical history of past generations. The evidence of a BRCA mutation in our family only becomes clear when aggregating the family history, stretching back to my great-grandparents and their siblings. Like the proverbial three blind mice, each branch of the family has only a small piece of the total information. BRCA mutations in your family might not be evident if you have information only for direct ancestors-- your parents and grandparents. Stronger evidence requires communication among branches of the family to establish a more complete picture.
The questions surrounding BRCA are wider in scope than an individual's medical decisions. Genetically inherited diseases require us to defy conventions about what medical information is appropriate or necessary to share with our families. This may make us uncomfortable, especially when we must reach out to relatives we don't see regularly. If we wish to avoid life-threatening cancers, we must reach out. We need a new rulebook for what is personal and private, and what comprises family knowledge. But it is clear that what we share- and when we choose to share it-- can go along way toward preventing cancers.