Genetic analysis of the polymorphisms in nonhomologous DNA end joining gene Ku70 and Ligase IV in postmenopausal breast cancer women

Aim: Breast cancer is one of the major killers worldwide. Aberrant double-stranded break (DSB) repair leads to genomic instability, which is a hallmark of malignant cells. Double-stranded breaks are repaired by two pathways: homologous recombination (HR) and nonhomologous DNA end joining (NHEJ). It is not known whether these repair pathways are affected in sporadic breast tumours.

Material and methods: In the present work the distribution of genotypes and frequency of alleles of the Ku70 gene, A46922G polymorphism and Ligase IV, A6008G (Ile591Val) polymorphism in breast cancer women were investigated. The genetic polymorphisms analysis was performed using a PCR-RFLP method in 135 sporadic breast cancer cases.

Results: The distribution of the genotypes of the A46922G polymorphism of the Ku70 gene in patients differed significantly (p < 0.05) from those predicted by the Hardy-Weinberg equilibrium. There were significant differences in the frequencies of alleles between the breast cancer subjects and controls (p < 0.05). However, the distribution of the genotypes of the A6008G polymorphism of Ligase IV in both control and patients did not differ significantly (p > 0.05) from those predicted by the Hardy-Weinberg distribution.

Conclusion: The results support the hypothesis that the A46922G polymorphism of the Ku70 gene may be associated with the incidence of breast cancer in postmenopausal women from the Łódź region of Poland.