Is Breast Cancer Hereditary? A HealthCentral Explainer
Can you inherit breast cancer? In rare cases, a mutated gene that greatly elevates breast cancer risk is passed from one generation to the next. Somewhat more frequently, a family history of the disease, without any identified genetic marker, is responsible for putting a woman at increased risk for breast cancer. But in over 80% of breast cancer diagnoses, there's no family history at all.
Do you worry about inheriting breast cancer because your grandmother had it? Or a great aunt, or your dad's sister?
That's one stressor you can probably eliminate from your life. So far as research currently shows, less than 1% of the population is at risk of inheriting breast cancer via a parent.
Not to say that figure won't change in the decades to come; researchers are operating under the belief that breast cancer has more genetic causes that have yet to be identified. But for now - any anxiety you have about inheriting breast cancer is probably unfounded.
Still, heredity does play some role in breast cancer risk, as follows:
BRCA1 and BRCA2 genetic mutations
What exactly are these genetic mutations? BRCA1 and BRCA2 are genes that manufacture proteins that help DNA repair itself. When those genes mutate and no longer manufacture the protein, DNA tends to become damaged, which leads to mutations, which can lead to cancer. Mutations in either of the BRCA (BReast CAncer) genes are inherited; thus identifying a mother or grandmother, sister or aunt with a BRCA gene mutation points to others in her family having the same mutation - and thus being more likely to develop breast cancer (as well as ovarian cancer).
Ashkenazi Jewish women carrying these genes are at highest risk of developing breast cancer: fully 65% of these women will be diagnosed with breast cancer by age 70, as compared to 12% in women without the mutated gene. In addition, hispanic women and young black women are more likely than non-hispanic white, Asian, and older black women to carry mutated BRCA1 and BRCA2 genes. (2008, Hamel)
Do you feel you might be a BRCA carrier? For guidance on whether or not you should pursue testing, read our post BRCA Genetic Testing: Yes or No?
"Cancer runs in my family," you think. "Does this mean I'm at greater risk of getting breast cancer?"
The bad news is yes - but only in specific cases. If a first-degree relative (parent, sibling, child) has been diagnosed with breast cancer, your personal risk is greater than normal; about 13% of women diagnosed with breast cancer fall into this specific category. If a relative's diagnosis came before age 50, your risk is even higher - about double the normal risk.
The good news is, based on current research, even three uncles with prostate cancer, both grandparents having lung cancer, and two cousins with lymphoma don't increase your risk of being diagnosed with breast cancer. In short, family history with regard to breast cancer risk is limited to immediate family.
Bottom line: breast cancer can be hereditary. But lifestyle choices (being overweight, drinking, not exercising, eating an unhealthy diet) are much more likely than family genetics to increase your risk of breast cancer.
Family history of breast, ovarian or prostate cancer. (2013, November 11). Retrieved from http://ww5.komen.org/BreastCancer/FamilyHistoryofBreastOvarianorProstateCancer.html
Hamel, P. (2008, January 08). BRCA1: Startling new findings point to need for wider testing. Retrieved from http://www.healthcentral.com/breast-cancer/c/78/18480/brca1-wider