HEREDITARY BREAST-CANCER AND FAMILY CANCER SYNDROMES

Hereditary breast cancer (HBC) shows extant clinical and genetic heter ogeneity. Clinically one finds the onset of breast cancer at an early age, an excess of bilaterality, and patterns of multiple primary cance r such as combinations of breast and ovarian carcinoma in the heredita ry breast-ovarian cancer (HBOC) syndrome. In addition to HBOC, one see s a variety of putative breast cancer-prone genotypes inclusive of her editary site-specific breast cancer, and the Li-Fraumeni (SBLA) syndro me that is characterized by cancers involving all three germinal layer s including sarcomas, brain tumors, leukemia, lymphoma, and adrenal co rtical carcinoma in addition to often markedly early-onset breast canc er. Breast cancer is also associated with autosomal dominantly inherit ed Cowden's disease and autosomal recessively inherited ataxia-telangi ectasia. Examples of pedigrees depicting clinical examples of these se veral HBC syndromes are presented in order to describe HBC's heterogen eity. The recent identification of the BRCA1 gene in early-onset hered itary site-specific breast cancer and the HBOC syndrome has led to new challenges for the genetic counselor. We review genetic counseling, w hich embraces surveillance and management recommendations that are res ponsive to the natural history of HBC and address the concept for futu re development of centers of expertise for HBC in the interest of impr oving cancer control.