We investigated the roles of MTA1 and MTA2 in the metastasis of the ZR-75-30 luminal B breast cancer cell line [20, 21], and we found that the overexpression of MTA1 inhibits the metastasis of ZR-75-30 cells by downregulating MTA2, which has not been clarified previously [19]. This evidence concerns the gene MTA1 and breast cancer.