Clinico-pathological characteristics of BRCA1-and BRCA2-related breast cancer

Approximately 2% to 5% of all breast cancers are hereditary, meaning that t he cancer predisposition is carried as a monogenic trait. Several highly pe netrant breast cancer predisposing genes have been identified. These discov eries will permit a refined description of breast cancer occurring as part of the different genetic syndromes. We reviewed the medical literature on t he clinico-pathological features of breast cancer associated with the major breast cancer susceptibility genes BRCA1 and BRCA2. BRCA1-associated breas t cancers are more frequently ductal invasive, high-grade carcinomas with a n important lymphocytic infiltration. They are aneuploid, estrogen and prog esterone receptors negative, and p53 positive. BRCA2-related breast cancers tend to be higher-grade tumors than are non-hereditary cases, although thi s association is less strong then for BRCA1 cases. These tumors exhibit sub stantially less tubule formation, but mitotic count and cellular pleomorphi sm do not differ significantly from those of sporadic cases. The overall pa ttern of the identified pathological characteristics suggests a carcinogeni c pathway in BRCA1- and BRCA2-related breast cancers differ ent from that f ound in sporadic cases. The probability of finding a BRCA1/2 germ-line muta tion is partly determined by these characteristics. In addition, these feat ures will likely influence the behavior of BRCA1/2-related breast cancer. S emin. Surg, Oncol 18:287-295, 2000, (C) 2000 Wiley-Liss, Inc.