BRCA1 Mutation In Human Breast Cancer

OBJECTIVE The hereditary breast and orarian cancer susceptibility gene(BRCA1) is known as a kind of anti-oncogene. This study was to assay BRCA1 gene mutation in breast cancer, and to study the relationship between BRCA1 mutation and breast cancer. METHODS Breast cancer tissues of 89 patients were studied, and breast tissues of 30 cases of patients without cancer were randomly selected as controls. Each tissue sample was ground thoroughly in mortar with pestle. DNA was extracted by the phenol-chloroform method. To determine the concentration and purity of the DNA solution, the absorbance of UV light is measured in a spectrophotometer. Fragments of exon2, 3, 5, 8, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20 and 21 of BRCA1 gene were amplified by PCR. Mutational screening was performed by single-strand conformation polymorphism analysis(SSCP), and alterations were confirmed by DNA sequencing. RESULTS A total of 9 single nucleotide changes in BRCA1 were identified, including 2 missense mutations in exon 5(273C>G, 287A>T), 1 missense mutation in exon 12(4285G>A), 2 missense mutations in exon 17(5115T>C, 5116A>G), 2 missense mutations in exon 18(5206T>A , 5214C>T), and 2 polymorphisms in exon 3(233G>A). the mutation ratewas 7.9%(7/89). No mutation was identified in the controls. CONCLUSIONS Mutations in BRCA1 is closely related to breast cancer, and BRCA1 mutation may play an important role in the development of sporadic breast cancer in southern Chinese populations.