Cancer prevalence in 129 breast-ovarian cancer families tested for BRCA1 and BRCA2 mutations

Women who carry germline mutations in the breast-ovarian cancer susceptibility genes, BRCA1 and BRCA2, are at very high risk of developing breast and/or ovarian cancer. Both genes are tumour suppressor genes that protect all cells from deregulation, and there are reports of their involvement in other cancers that vary and seem to depend on the population investigated. It is therefore important to investigate the other associated cancers in different populations to assist with risk assessments. To assess the cancer risk profile in BRCA-mutation-positive and negative South African breast-ovarian cancer families, mainly of Caucasian origin. Descriptive study in which the prevalence of all cancers in the pedigrees of BRCA1- and BRCA2-mutation-positive groups and a group of families without mutations in either gene were compared with the general population. As expected, female breast and ovarian cancer was significantly increased in all three groups. Furthermore, male breast cancer was significantly elevated in the BRCA2-positive and BRCA-negative groups. Stomach cancer prevalence was significantly elevated in the BRCA2-positive families compared with the general population. These results can be applied in estimation of cancer risks and may contribute to more comprehensive counselling of mutation-positive Caucasian breast and/or ovarian cancer families.