BRCA1 And BRCA2 Gene Mutations In Human Sporadic Breast Cancers

OBJECTIVE The hereditary breast and ovarian cancer susceptibility gene including BRCA1 and BRCA2, is known as a kind of anti-oncogene. This study was to assay BRCA1 and BRCA2 gene mutation in sporadic breast cancer, and to study the relationship between BRCA1 and BRCA2 mutation and breast cancer.METHODS Breast cancer tissues of 144 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, exon3, exon 5, exon6, exon7, exon8, exon9, exon10, exon11, exon12, exon13, exon14, exon15, exon16, exon17, exon18, exon19, exon20, exon21, exon22, exon23, and exon24 in the BRCA1 gene and exon10 and exon14 in the BRCA2 gene were amplified by PCR. Mutational screening was performed by single-strand conformation polymorphism analysis(SSCP), and alterations were confirmed by DNA sequencing. The amplified fragments of exon2 and exon3 which were not suitable for SSCP (>300bp) were sequenced directly. The pathological and immunohistochemical features of BRCA1 mutation associated breast cancer were studied with the no mutation group .RESULTS A total of 20 single nucleotide changes in BRCA1 were detected in the 144 cases of breast cancer patients, including 2 same polymorphisms in exon 3(233G>A), 2 missense mutations in exon 5(273C>G, 287A>T), 1 missense mutation in exon 9(690G>A), 2 polymorphism in exon 11(2430T>C, 2630T>G), 8 missense mutations in exon 11(2532T>G, 2685T>C (2cases) , 3191C>G,...