Summary: The gene for heritable breast and ovarian cancer BRCA1 has been recently cloned using the general strategy of positional cloning. The gene is localised on the long arm of human chromosome 17; it is composed of 22 exons distributed over 100 kb of DNA and codes for a 1863 amino acid long protein with a zinc finger domain in its N-terminal part. The gene is mutated in cancer families but only infrequently in sporadic ovarian cancer, with virtually no somatic mu tation having been found to date found in sporadic breast cancer. Its expression is, however, markedly reduced in most spontaneous breast carcinomas. The expression of the mouse homo-logue BRCA1 suggests an important role in breast development. The exact biological function of BRCA1 as well as its role in carcinogenesis remain, however, to be elucidated.
The Cloning of heritable breast and ovarian gene BRCA 1 - from molecular genetics to clinical oncology
