Clinical relevance of CHEK2 and NBN mutations in the macedonian population

Clinical importance of the most common CHEK2 (IVS2+1 G>A, 1100delC, I157T and del5395) and NBN (R215W and 657del5) gene mutations for breast cancer development in Macedonian breast cancer patients is unknown. We performed a case-control study including 300 Macedonian breast cancer patients and 283 Macedonian healthy controls. Genotyping was done using a fast and highly accurate single-nucleotide primer extension method for the detection of five mutations in a single reaction. The detection of the del5395 was performed using an allele-specific duplex polymerase chain reaction (PCR) assay. We have found that mutations were more frequent in breast cancer patients (n = 13, 4.3%) than in controls (n = 5, 1.8%), although without statistical significance. Twelve patients were heterozygous for one of the analyzed mutations, while one patient had two mutations (NBN R215W and CHEK2 I157T). The most frequent variant was I157T, found in 10 patients and four controls (p = 0.176) and was found to be associated with familial breast cancer (p = 0.041). CHEK2 1100delC and NBN 657del5 were each found in one patient and not in the control group. CHEK2 IVS2+1G>A and del5395 were not found in our cohort. Frequencies of the studied mutations are low and they are not likely to represent alleles of clinical importance in the Macedonian population.