The genetic makeup of every individual consists of BRCA 1 and 2 (Breast Cancer genes) which are tumor-suppressing genes that help to fight cancer. However, these genes undergo mutation (a change in the DNA sequence that makes up a gene). The Center for Disease Control (CDC) reports that in Ashkenazi Jewish women, about one in 40 have this BRCA mutation.
The mutations of these suppressing genes increase the probability of individual developing breast cancer at a very early age. It does this not only for breast cancer but also for various other cancers. If you’re an Ashkenazi Jewish woman and any of your parents has a BRCA mutation, there’s a 0.5 out of one probability that you have the same mutation. Consequently, this means you stand a great chance of developing breast cancer.
If any immediate family e.g. sister, mother, daughter, or more than one second-degree relative from either parent’s side of the family i.e. grandmother, niece, or aunt has been diagnosed with ovarian or breast cancer, you should consider signing up for genetic counseling.
It is, however, worthy of note that not every woman with these BRCA mutations will develop cancer; it just increases the chances. Study shows that in the U.S. population about 50 out of 100 women with the mutated BRCA gene will develop breast cancer before the age of 70, while only 7 out of 100 without it will develop breast cancer. Also, for ovarian cancer 30 out of 100 women with mutated BRCA genes will develop it while only one out of 100 will for those without it.
It is, therefore, imperative that you understand your health conditions and take steps that might help prevent or treat breast or ovarian cancer at an early age.
Source:https://www.cdc.gov/cancer/breast/young_women/bringyourbrave/hereditary_breast_cancer/jewish_women_brca.htm (Subscription may be required)