After a couple of recent messages from readers, I realized that I don’t talk about my genetic status much … you have to do some digging to figure that out. Well, I’ve updated my About page and here I am clarifying: I am a BRCA uninformed negative. If you’re already confused, scroll down for an explanation of BRCA and its significance in the cancer world.
What is an uninformed negative?
There is a distinction between a positive genetic test result and a negative one, obviously, but there is a further separation between true negative and uninformed negative. The former diagnosis is made when a mutation has already been identified in the family line, but the person tested does not carry that mutation. The latter applies to individuals like me, whose family tree DNA does not present any known mutations associated with the increased occurrences of cancer. It is still a mystery and we remain uninformed.
Aside from the most commonly tested BRCA1 and BRCA2 genes, there are many others that impact risk of breast and ovarian cancer, such as PTEN, CHEK2, ATM, TP53. The clinical significance of mutations on those genes varies from that of BRCA mutations, however. My genetic counselor and I are discussing testing for these. I am aware that it is possible my sister and mother, who both died from gynecologic cancers, carried some gene mutation their limited testing did not uncover and I did not inherit it, so we are considering importing my mother’s blood sample from Europe to be thoroughly tested in the US. To find out how to assess your risk, learn more about counseling, or find a certified counselor, visit FORCE.
Also, if you are a fellow uninformed negative, there’s a Facebook group for that! Join us.
Now, for the nuts and bolts of this …
What is BRCA?
Everyone has four BRCA (BReast CAncer) genes: one copy of BRCA1 inherited from mom, one from dad and same of BRCA2. They produce tumor suppressor proteins, which help repair damaged DNA. Mutations present in these genes result in production of defective proteins unable to do their job, which can result in genetic alterations and ultimately lead to cancer.
Together, BRCA1 and BRCA2 mutations account for about 20 to 25 percent of hereditary breast cancers and about 5 to 10 percent of all breast cancers. In addition, mutations in BRCA1 and BRCA2 account for around 15 percent of ovarian cancers overall. Breast cancers associated with BRCA1 and BRCA2 mutations tend to develop at younger ages than sporadic breast cancers. – National Cancer Insitute
An important thing to note: as long as an individual has one properly functioning gene, they are producing those DNA-repairing proteins and remain protected. Not until the second copy of the gene is mutated does their chance of developing cancer skyrocket. Somatic mutations can occur due to exposure to carcinogens, such as certain chemicals found in prepared foods (I’m looking at you, hot dog), cigarette smoke, asbestos, radiation, alcohol, etc. Eat healthy, live clean, wear sunblock, lay off the booze!
This is a really great video shared by Andrea on her blog Brave Bosom. It explains mutations, how they relate to cancer, and how treatment affects cells.
Genetic testing can determine whether an individual is a carrier of a known BRCA mutation. There are well over three thousand BRCA mutations that have been identified, however not all of them are clinically significant, which means they either don’t increase risk of these cancers or we don’t yet have enough data to comfortably say so. Here is the break down according to another blogger’s analysis of data available from the National Human Genome Research Institute’s Breast Cancer Information Core database (say that three times fast!). Although this database contains a wealth of data, this analysis is from a specific point in time. New mutations are discovered every day! If you’re a data nerd, hop over to Jessica’s blog to read the full post and her story: Breaking BRCA.
*Please note that I am not a genetic counselor or a healthcare professional and am only presenting my experience and what I leaned from doing my own research. Please consult a doctor or certified genetic counselor if you have questions or concerns about your own genetic status and associated health.
Previous posts on the topic:
- BRCA mutations made simple
- Genetic testing for BRCA mutations
- Letters to Doctors: The BRCA and HBOC Syndrome Edition