Cancer risks associated with the genes BRCA1 and BRCA2

ABSTRACT

Inherited predisposition to breast and ovarian cancer, which accounts for about 5 to 10% of these cancers, has been associated with mutations in the BRCA1 and BRCA2 genes. Mutations in both of these genes increase the lifetime risk of developing breast cancer by approximately 80%. Whilst BRCA1 confers a greater predisposition of ovarian cancer, BRCA2 has been associated with male breast cancer. Both genes code for large proteins and display a number of similar features including a large internal exon 11, expressed in similar tissues, and possess a number of similar putative functional domains. Furthermore, both proteins appear to act as tumour suppressor genes and may play a role in the DNA repair process. It is becoming increasingly important to identify families whose cancers may be due to these highly penetrant disease genes. Individuals who undergo predictive genetic testing will need appropriate support and counselling prior to their cancer risk assessment. For those at risk, appropriate counselling, laboratory services, screening and management need to be made available