Breast Cancer Susceptibility Genes

In 1994 and 1995 two geneswere identified that
confer susceptibility to breast and ovarian
cancer when mutated, the breast cancer genes
BRCA1 and BRCA2. Both genes encode multifunctional
proteins with important cellular
functions in genomic stability, homologous recombination,
and double-stranded and transcription-
coupled DNA repair (see p. 80). The
BRCA1 and BRCA2 proteins interact and play a
role in cell cycle control (see p. 112) and in
development. An autosomal dominant susceptibility
mutant allele in one of these genes is
considered the main cause of the cancer in
about 5–10% of patients. Mutations in other
genes are involved in some cases. The direct
causative role of BRCA1 and BRCA2 mutations is
difficult to assess in individual patients. Different
mutations as well as polymorphic variants
occur throughout the genes.