[The clinical study of familial breast cancer - now and the problems].

The clinical features of familial breast cancer are characterized by early onset, high frequency of bilateral breast cancer, and multiple malignancies of other organs. It is strongly suggested that genetic factors contribute to familial breast cancer. The causative genes now identified are BRCA1 and BRCA2. This disease is called hereditary breast ovarian cancer syndrome (HBOC)because breast cancer and ovarian cancer are clustered in the kindred confirmed BRCA mutation. As for BRCA related breast cancer, early onset and highly frequent bilateral breast cancer are characteristic. In addition, the histological grade is high and the positive rate of estrogen receptors is low in BRCA1-related breast cancer. Gene diagnosis of BRCA is useful when choosing a surgical method, chemotherapy, or a surveillance of mutation carriers. The problem in Japan is that the treatment is very expensive, with poor understanding of HBOC of by clinicians and as yet immature genetic counseling system.