BRCA1 Gene Exon2 And Exon20 Mutation Detection Of Familial Breast Cancer And Early-onset Breastcancer From Qingdao In CHINA

Objective Breast cancer is one of the most common malignancy among women.BRCA1(breast cancer gene 1) is the tumor suppressor genes that most closely related to breast cancer.At present foreign and domestic other groups have conducted extensive research and found some founder mutations,which benifit in early census and early preventive intervention. On this study we detect the mutation sites of BRCA1 gene exon2 and exon20 in familial breast cancer and early-onset breast cancer in Qingdao and to study the relationship between BRCA1 gene mutation and breast cancer.Methods Fifty-five familial and/or early-onset breast cancer patients from unrelated families were analyzed.Genomic DNA were collected from paraffin-embedded specimens.Two pairs of primers were designed for the PCR amplications on exon 2 and exon 20 of BRCA1.The partial exons(2,20) of BRCA1 gene in 55 breast cancer patients were analyzed by polymerase chain reaction(PCR) and direct DNA sequencing.Results One kind of disease-related mutation on the exon 2 of the BRCA1 gene(176 G＞C) was found in one unrelated family,the mutation rate is 1.8% (1/55).The case was a familial breast cancer patient,so the mutation rate was 3.3%(1/30) in familial breast cancer patients.No pathogenic mutation was found on the exon 20 of the BRCA1 gene in 55 cases of breast cancer.Conclusions The mutation on the exon 2 of the BRCA1 is involved in carcinogenesis of the familial breast cancer,but the gene sequence of what we have studied on exon 2 and exon 20 of BRCA 1 doesn't account much for occurrence of the early-onset breast cancer in Qingdao,China.It is important to find new mutations at the other gene loci in BRCA1 gene.