RESUMO
BACKGROUND: NBS1 gene, which product participates in DNA repair, has been postulated to be a susceptibility factor for a number of types of cancer, including breast cancer. The carrier frequency of the 657del5 and I171V NBS1 gene mutations among Polish patients with familial breast and/or ovarian cancer was compared with that of randomly selected newborns. PATIENTS AND METHODS: Using allele-specific amplification-polymerase chain reaction (ASAPCR) and restriction fragment length polymorphismpolymerase chain reaction (RFLP-PCR) techniques, blood samples were analysed from 250 patients with breast or/and ovarian cancer and a total number of 4,000 for 657del5 mutation and 1,300 for I1171V mutation controls. RESULTS: Although an increased frequency of both mutations in cancer cases - 0.8% of 657del5 and 2.4% of I171V, compared to controls - 0.52% and 1.38%, respectively, was found, the differences were not statistically significant. CONCLUSION: Our results indicate that NBS1 mutations do not contribute significantly to breast or ovarian cancer development.