RAD51, RAD52, and RAD54 encode proteins that are critical to the repair of double-strand DNA breaks by homologous recombination. The objectives of this study were to determine the frequency of BRCA1 germ-line mutations and the RAD52, RAD54 and RAD54B microsatellite instability (MSI) and loss of heterozygosity (LOH) in patients with breast cancer.
Material and methods: Blood and tumour tissue were obtained from 100 breast cancer women. Blood samples age matched healthy individuals (n = 60) served as control.
Results: The microsatellite instability status was significantly higher in breast cancer tissue compared as control (p < 0.05). Significant correlation between one or more regions with concomitant LOH and pathologic parameters were observed with respect to progesterone receptors (p = 0.004) and tumour grade (p = 0.001). In present study one Ex20insC and two ExII17delA mutations of BRCA1 gene were identified in women with breast cancer.
Conclusion: The results suggest that the microsatellite instability and LOH seems to be important in the development sporadic breast cancer. The lack of detectable BRCA1 germ-line mutations in most cases suggests that there are probably additional, as yet unidentified genes predisposing to this disease.