Identification of Mutation in Exon11 of BRCA1 Gene in Bangladeshi Patients with Breast Cancer

Abstract

Background: Worldwide, breast cancer is the leading cause of cancer death in female, in Bangladesh breast cancer is the second leading cancer in both sexes, and in women it occupied the top position. Highly penetrant mutations in BRCA1 gene constitute high risk of breast cancer. The spectrum of BRCA1 gene mutations varies in different population. The objective of this study was to identify mutation in exon11 of BRCA1 gene in Bangladeshi breast cancer patients. Methods: Genomic DNA was extracted from the histopathologically diagnosed formalin fixed paraffin embedded (FFPE) breast cancer tissues of 65 adult female patients. Two regions of exon11 of the BRCA1 gene were amplified and the amplicons were sequenced using Sanger sequencing. The sequenced nucleotides were analyzed and blast using NCBI nucleoblast. Selected demographic, reproductive and medical histories were collected and analyzed using SPSS version 20. Results: The mean age of the patients was 46 years and the mean age at diagnosis was 44.64 years. The patients were married and had 2.65 ± 1.22 children except one was nulliparous, the mean age of menarche was 12.67 years. All patients had children, breastfed the babies for an average 1.5 years. Only 13.6% of the patients had hypertension and the rest had no comorbidity. The family history for cancer (breast and other cancer) was negative. Three novel mutations were found in a patient. Two among the three mutant sequences had effect on amino acid coding (DNA sequence change g.852G>C and g.709G>A and amino acid changes p.Gln284His and p.Glu237Lys respectively). Conclusion: We found three novel mutations in Bangladeshi breast cancer patients. This finding indicates the necessity to study the mutation profile of whole BRCA1 gene in our population for cancer risk prediction.