GERM-LINE MUTATION AT BRCA1 AFFECTS THE HISTOPROGNOSTIC GRADE IN HEREDITARY BREAST-CANCER

Histoprognostic grade is a determinant parameter to select the initial therapeutic strategy in breast cancer, Our aim was to analyze the gra de repartition in BRCA1-associated breast cancer (BC) and to explore t he possible connections between grade and the BRCA1 gene function, We first compared 27 BRCA1-associated BCs from 14 families with 4461 case s from an administrative district registry and 242 cases from a hospit al-based registry, matching for grade and constitutive elements, and t hen considered their repartition in families. We observed a prevalence of grade 3 (P < 0.0001) in BRCA1-associated BC. This was attributed m ainly to nuclear polymorphism (P < 0.0001), mitotic activity (P < 0.00 01), and tubular differentiation (P = 0.0004), implying that BRCA1-ass ociated BCs are highly proliferating tumors, Moreover, it is suggested that grade segregates as a genetic trait within families (P = 0.0015) , and this was attributed to the mitotic index segregation only (P = 0 .0005), Therefore grade, through its components, could be interpreted as the morphological translation of the BRCA1 germ line mutation. Thus , a genotype-phenotype correlation may exist between the type of mutat ion and the aggressiveness of the disease. These findings are bound to have an important impact in the care management of hereditary breast cancer at the individual and at the familial level and in the comprehe nsive approach of breast cancer development.