[Cytogenetic abnormalities, genetic alterations, and applications for genetic diagnosis in breast cancer].

The etiology of breast cancer involves a complex interplay of exogenous and endogenous factors, including genetic factors. The identification of oncogenes, tumor suppressor genes and human mismatch repair genes has helped to refine the characterization of breast carcinogenesis. The major types of genetic alterations in breast cancer are amplification of protooncogenes (ERBB2 and MYC) and DNA from chromosome band 11q13; mutation of p53; and loss of heterozygosity on 1p, 3p, 8p, 11p, 13q, 16q, 17p, 17q, 18q. The latter may imply inactivations of tumor suppressor genes. Recently, two distinct familial breast cancer susceptibility genes, BRCA1 and BRCA2, have been isolated. These findings enable to use these genes for genetic diagnosis in clinical oncology.