Thus, BRCA 1/2 germline pathogenic variants are highly ethnic-specific in BC patients, with a high frequency of BRCA variation in specific countries or ethnic groups, especially within genetically isolated populations, as well as other somatic and germline mutations in high- or moderate-prevalence genes, such as TP53, PI3KCA, CHEK2, BARD1, ATM and PALB2, which also emphasize racial differences. Here, CHEK2 is linked to breast cancer.