[Genes involved in breast cancers].

Specific abnormalities in cancers are the best molecular targets of therapeutics, which is exemplified by trastuzumab. ERBB2 amplification is present in 15-30% of invasive ductal carcinomas, and its overexpression was associated with poor prognosis. c-MYC amplification is present in 13-19%, but other forms of oncogene activation are rare. Germline mutations of BRCA1 and BRCA2 are responsible for familial breast cancers. Their somatic mutations in sporadic breast cancers are rare, but chromosomal losses are frequent. Inactivation of BRCA1 by its promoter methylation is also frequent. p53 mutations are present in 20-25% of sporadic breast cancers, and inactivation of its pathway is present in most of them. Further molecular analysis will reveal new targets for diagnosis and therapeutics.