Background: Breast cancer is the most common malignancy in Iranian women. Mutations in BRCA1 gene is one of the important genetic predisposing factors in breast cancer. This gene is a tumor suppressor that plays an important role in regulating the functions of RAD51 protein for strand invasion in homologous recombination repair.
Methods: The BRCA1 gene has amplified in the DNA isolated from breast cancer patients' leukocytes, using Polymerase Chain Reaction technique. The PCR products have sequenced using an automated DNA sequencer and subsequently obtained data have aligned with the human BRCA1 DNA sequences available online.
Results: In this study, we have considered nine different mutations on 60 examined chromosomes from 30 patients, living in Kerman province. A deletion of one adenine (c.1017delA) and insertion of one cytosine (c.969InsC) have found as the most frequent (20%) mutation in this survey. A substitution of thymine for adenine (c.999T>A) has detected as the second common BRCA1 gene defect (6.7%). The other mutations have identified as single nucleotide replacement including: c.792A>C, c.825G>C, c.822T>A, c.1068A>G, c.969A>T and c.966T>C.
Conclusion: The identified BRCA1 mutations were in accordance with the previous reports. To our knowledge, four mutations: (c.969InsC, c.792A>C, c.825G>C, c.822T>A) which have identified in this study, have not been previously reported in the literature. A larger cohort study would help identifying all relevant BRCA1 mutations in this population.
Keywords: BRCA1 gene; Breast cancer; DNA mutational analysis.