We screened a total of 229 TNBC patients regarding mutations in one of the following breast cancer susceptibility genes: BRCA1, BRCA2, ATM, CDH1, CHEK2, NBN, PALB2, RAD51C, RAD51D and TP53. In 57women (24.9%) we detected a pathogenic mutation, with a higher frequency (29.7%) in the group manifesting cancer before 60 years (Table 1). The gene discussed is CHEK2; the disease is breast cancer.