Age at onset of bilateral breast cancer, the presence of hereditary BRCA1, BRCA2, CHEK2 gene mutations and positive family history of cancer.

BACKGROUND: Our research focused on the relations between the age at onset of bilateral breast cancer and the prevalence of selected hereditary BRCA1, BRCA2 and CHEK2 gene mutations with reference to their positive family history of cancer.
METHODS: The DNA of peripheral blood lymphocytes of patients was examined for the presence of selected hereditary mutations in the BRCA1, BRCA2 and CHEK2 genes, using molecular biology techniques. The family history of neoplasms was also analyzed.
RESULTS: The following mutations in the BRCA1 gene were identified: 185delAG, C61G, 5382insC, 3875 del11ins7, and R1751X. In the BRCA2 gene, the 9631delC and A9599T mutations were found. In the CHEK2 gene, the 1100delC and I157T mutations were identified. BRCA1/2 gene mutations were identified in 19.4% of patients and CHEK2 gene mutations in 7%.
CONCLUSIONS: It was shown that the presence of the mutations in the BRCA1/2 genes among patients with bilateral breast cancer is associated with an earlier occurrence of the first and the second breast cancer than in patients without hereditary mutations in these genes (a difference of 7.2-8.4 years). In patients with CHEK2 gene mutations, breast cancer occurred 2.1-3.8 years earlier than in patients without mutations in the CHEK2 gene. Copyright 2009 S. Karger AG, Basel.