Mutation Detection in the BRC A1 Among Filipino Breast Cancer Patients Using the Protein Truncation Test (PTT) and Single-Strand Conformational Polymorphism (SSCP)

Abstract

BRC A1 is a tumor-suppressor gene responsible for the inhibition of breast epithelial cell proliferation. The presence of a mutation in this gene increases the risk of an individual's susceptibility to breast cancer. This study was performed to detect the presence of mutations in the BRC A1 gene in selected Filipino breast cancer patients. Molecular analysis of the gene was done using the Protein Truncation Test (PTT) and Single-Strand Conformation Polymorphism (SSCI'). Results of the PTT analysis show that there are 110 mutations in exon 11 for the 13 samples. SSCP results show the presence of putative polymorphisms in exons 2, 5, 15, 16, and 18. Exons 20, 22, and 24 have negative results for SSCP analysis. The occurrence of breast cancer, in the case of the 13 samples included in this study, cannot therefore be linked to a truncated protein in exon 11 of the BIU 'A I, as analyzed using PTT. Furthermore, the presence of genetic aberrations in the other exons detected using SSCP cannot also be sufficiently associated with breast cancer unless the specific mutational event is identified. It is thereby recommended that DNA sequencing be done on the exons with aberrant bands in order to classify the exact mutation. For future studies, an increase in the number of samples would probably result in a higher probability of detecting mutations attributed to breast cancer.