Etiology and Clinical Features of Hereditary Breast and Ovarian Cancer (HBOC)
The genetic basis of HBOC is a germline mutation in either the BRCA1 or BRCA2 genes. Normally, the proteins encoded by BRCA1 and BRCA2 genes prevent cells from becoming malignant by helping to repair mutations that occur in other genes—making them tumor suppressor genes. But an inherited mutation within either of these genes greatly increases the probability of malignant transformation and cancer.
The association of BRCA1 and BRCA2 mutations primarily with breast and ovarian cancer is not yet fully understood, but is thought to be related to estrogen receptor expression in these tissues.
Approximately 7% of breast cancer and 11 - 15% of ovarian cancer cases are thought to be associated with an autosomal dominant pattern of inheritance of BRCA1 and BRCA2 gene mutations.8 When assessing hereditary cancer risk, a patient’s family history is collected to investigate the risk for HBOC. Genetic testing, however, provides the most accurate cancer risk assessment profile for an individual at risk for HBOC.
Example of a male carrier with an autosomal dominant mutation —
2 affected children and 2 unaffected children
