The CHEK2 1100delC mutation is not present in Korean patients with breast cancer cases tested for BRCA1 and BRCA2 mutation.

The germline CHEK2 1100delC mutation is a low penetrance breast cancer susceptibility allele, frequently observed in patient with family history of breast cancer and/or young age and the frequency varied according to race or ethnicity. In this study, we evaluated the significance of CHEK2 1100delC in predisposition to breast cancer by assessing its frequency in a material of 493 Korean breast cancer patients who had been screened for BRCA1 and BRCA2 mutations (42 patients had deleterious mutation of BRCA1/2). Mutation detection of CHEK2 1100delC was based upon analysis of primer extension products generated for previously amplified genomic DNA using a chip based MALDI-TOP mass spectrometry platform. After overall measurement automatically, assays which had bad peaks were checked again manually. None of the 493 Korean patients with breast cancer who were candidate for BRCA1 and BRCA2 test carried the 1100delC mutation observed in Caucasians with limited frequency. In the previous studies, we observed higher or comparable prevalence of BRCA1 and BRCA2 mutations in Korean patients with breast cancer compared to Caucasian breast cancer population. In the present study, we evaluated the role of a CHEK2 1100delC as a susceptibility mutation of breast cancer in the Korean population. However, our results suggest that this mutation is absent or may be very infrequent in Korean patients with breast cancer who have high risk of BRCA1 and BRCA2 mutation, making its screening irrelevant from the practical point view.