BRCA1 and breast cancer: The incidence of BRCA1/2 mutations in a group of Czech women with early onset non-familial BC was 12.9% (4/31; Table 3), whichsuggests that the age at diagnosis in patients with a negative family history is an important indicator for the presence of a pathogenic mutation and lends support to the screening of BRCA1/2 genes in patients with early onset disease.