Recently, there was much press about Angelina Jolie and her double mastectomy. She reported that she has a genetic mutation in BRCA1, which greatly increases her risk of breast and ovarian cancer. Her mother died from ovarian cancer and she decided to be proactive in reducing her cancer risk. Read her formal press release here Angelina Jolie BRCA announcement
Yes indeed, cancer risk can be inherited. In fact, there are many other mutations, aside from BRCA1 and BRCA2. Here are a few facts to keep in mind:
- Cancer-predisposing mutations are rare, but cancer risks can be very high. Consider BRCA1, seen in only 1 in 400 of the non-Ashkenazi Jewish population (1 in 40 of Ashkenazi Jews), but causing breast cancer risk to be increased to about 90% over a lifetime and ovarian cancer risk increased by about 59% by the age of 70.
- Mutations in a single gene may cause different cancers. BRCA mutations may predispose to breast and ovarian cancer, as well as cancers of the pancreas and prostate. Further, men with BRCA mutations have a much higher risk of male breast cancer. A genetic syndrome called Lynch syndrome is associated with cancers of the uterus, colon, and ovaries, among others.
- Many different genes and many different mutations. A rapidly increasing number of genes are recognized as having mutations that may add to cancer risk. Note that having the gene is not the problem, as most of these genes have very important functions in a healthy body. Problems such as cancer risk arise when such normal genes carry a mutation, or abnormal message that makes the gene function in a detrimental manner. BRCA1, BRCA2, TP53, PTEN are examples. BRCA genes have hundred of possible mutations that have been identified although not all are known to increase cancer risk.
- It is best to test a family member with cancer. Consider again that there are many possible mutations in each gene, and that only some mutations are clearly associated with cancer while others are in doubt. If a questionable mutation is found in an individual with cancer, it is easier to consider whether it may be cancer-causing for their particular family. On the other hand, finding a doubtful mutation in an unaffected member only raises more questions.
- There are options to reduce cancer risk. Having identified a cancer predisposing mutation, there is much that can be done to reduce risk. Organs can be removed (like breasts and ovaries), more intensive screening protocols can be followed (like alternating MRI and mammogram to detect breast cancer earlier), and medications can also be used. For example, individuals with BRCA mutations diagnosed with cancer in one breast, may have risk of a new cancer in the other breast reduced by 50% if they take a medicine called tamoxifen for 5 years.
Please note that the medical information I share is meant to be a general guide, not a substitute for medical advice from your physician. Any communication or writing here is not intended to establish a physician-patient relationship. The exact approach in treating a medical condition, including cancer, in any particular individual, depends on many variables so please be sure to discuss your thoughts and questions with your physician.
In the near future, I will write about personal and family history aspects that should raise concern about a possible genetic cancer predisposition. Do you have any other thoughts? Please feel free to leave a comment below.