Substitutions of the NBS1 gene and clinicopathological characteristics of young breast cancer patients

* Corresponding author. Email: roberta.vadeikiene@lsmuni.lt; r.jankauskaite@gmail.com The purpose of this study was to determine characteristics potentially related to NBS1 mutations and polymorphisms in young (≤50 years of age) breast cancer patients. Blood from 80 breast cancer patients was collected. NBS1 mutations c.657_661del, p.R215W, p.I171V, and polymorphisms c.8360G>C, c.30537G>C were genotyped by the PCR-RFLP method. Two-sided Chi-square test was used for univariate analysis and logistic regression analysis was used to evaluate the odds ratio. No carriers of the c.657_661del, p.R215W and p.I171V mutations were found. NBS1 c.8360G>C logistic regression analysis showed that GC and CC genotypes compared with GG genotype had decreased risk of low grade tumour, 2.885-fold (OR = 2.885, 95% CI 0.173–0.735, P = 0.005) and 2.186-fold (OR = 2.186, 95% CI 0.188–0.888, P = 0.024), respectively. 8360 CC genotype (OR = 3.034, 95% CI 0.156–0.778, P = 0.010) significantly increased the chances of HER2 amplification compared to GG genotype. NBS1 8360 GC genotype had a higher risk for breast cancer progression (OR = 1.673, 95% CI 0.233–0.915, P = 0.027). The homozygote 8360 CC carriers had approximately a six times higher risk for the disease progress (OR = 5.946, 95% CI 0.098–0.585, P = 0.002). The prevalence of triple negative breast cancer type was significantly higher in individuals with NBS1 8360 CC genotype (OR = 2.186, 95% CI 0.188–0.888, P = 0.024). Regarding c.30537G>C polymorphism, none of the genotypes had a significant influence on pathological characteristics. NBS1 gene c.8360G>C polymorphism might be associated with breast cancer aggressiveness in young breast cancer patients.