Known mutated drivers of primary breast were frequently mutated in BCBM including TP53, MLH1, PIK3CA, and KIT. When we analyzed matched pairs of primary BC and BCBM, genetic alterations such as TP53, PIK3CA, KIT, MLH1, and RB1 were detected in both primary BC and BCBM in the same patients. Here, MLH1 is linked to breast cancer.