Analysis of BRCA1 Exon 2 Mutations in FFPE Tissues of Bangladeshi Bangali Females with Breast Cancer

Abstract

Background: Among all breast cancers, 5 to 10% are hereditary and related to mutation of BRCA1 and BRCA2 gene. To date, extensive researches have been carried out for detection of mutations in the exon2 of BRCA1 gene. Genetic study on these two genes from formalin-fixed paraffin-embedded tissue in Bangladeshi population has not been reported so far. Objective: To identify mutation in exon2 of BRCA1 gene from formalin-fixed paraffin-embedded tissue of adult Bangladeshi Bangali female patients with breast cancer. Methods: The research was cross-sectional descriptive type of study. The study was conducted on Adult Bangladeshi Bangali female patients with breast cancer aged more than 18 years. A questionnaire was developed to record information on socio-demographic and reproductive characteristics. The data was analyzed by SPSS (Statistical package for the social sciences) version 23.0. The whole sequence of exon2 of chromosome 17 was amplified by short range PCR using the Gotaq master mix and primer sequence. The amplicons were confirmed by 2% agarose gel electrophoresis and sequencing was done by Sanger sequencer. Data analysis was performed using Chromas® software version 2.33 and Mega 7 software. The quary sequences were compared with the NCBI database. Results: Average age of the breast cancer patients was 45.46 (± 11.52) and the mean age at menarche was 12.46 (± 0.646). In this study, new mutations along with known mutations were found in exon2 of BRCA1 gene of eight adult female breast cancer patients. The mutations are insertions (C>A, C>T, T>A, G>T, G>C, T>C, A>T, C>G), deletion (C_) and single nucleotide substitution (T-C, G-A, T-G, C-G, T-A, G-C, C-A) in types. Conclusions: The aim of the research was to identify mutation in exon2 of BRCA1 gene. Eight patients have mutation in their DNA sequence revealed from formalin-fixed paraffin-embedded tissue. Further studies are required to evaluate whether these mutation contribute to breast cancer or not. Identification of known mutation along with new mutation with this small sample size emphasizes the importance of exploration the genetic makeup of Bangladeshi population to develop a database for proper screening and genetic counseling of the disease.