Heredity and breast cancer
Breast Cancer represents 30% of all malignant neoplasms in the female population. At least 10% occur in women who have mutations in genes of high (BRCA1&2) or moderate (PALB2, CHEK2, ATM) penetrance (Hereditary Cancer).
A lesion (mutation) in the BRCA1&2 genes increases the relative risk of developing breast cancer 5-10 times, while in the PALB2, CHEK2, ATM genes 1.5-5 times. The majority (~80%) of hereditary breast cancers result from mutations in the BRCA1&2 genes.
A woman should undergo genetic testing when her personal history includes several relatives with breast and/or ovarian cancer, breast cancer in a relative at a young age (<50 years), a relative with bilateral breast cancer, a male relative with breast cancer, a relative with ovarian cancer and of course when there is a relative with a positive genetic test.
The result of the genetic test can be:
- NEGATIVE: no clinically significant mutation has been identified but the risk of the general population remains
- POSITIVE: pathogenic mutations have been identified
- OF UNKNOWN CLINICAL SIGNIFICANCE: there are mutations that have not yet been characterized as pathogenic or benign.
In women with a genetic mutation in the BRCA1&2 genes, “preventive measures” that can be taken are: Intensive monitoring for the purpose of early diagnosis, Modification of risk factors for breast cancer development (e.g. avoiding obesity, long-term hormone therapy, etc.), Chemoprophylaxis with Tamoxifen or Aromatase Inhibitors and finally, the active but most effective solution of Bilateral Prophylactic Mastectomy (risk reduction >95%) and Salpingo-Oophorectomy.
Among breast cancer patients, those diagnosed at age <45 or diagnosed at any age and a family member (parents, siblings, children) diagnosed at age <50, two or more family members with breast, pancreatic and/or prostate cancer should undergo genetic testing. Also, those diagnosed with Triple Negative Breast Cancer at age <60, personal or family history of ovarian cancer or history of breast cancer in a male family member.
