MTA1 is an essential component of the nucleosome remodeling and histone deacetylation (NuRD) complex, which provides the opportunity for MTA1 to participate in the regulation of the MAPK/Erk pathway, Wnt pathway, DNA damage repairment, and ubiquitination pathway, which are closely involved in chemotherapy resistance, radiation resistance, tumor invasion, and regression in breast cancer, ovarian cancer, and colorectal cancer, (22, 23). The gene discussed is MTA1; the disease is breast cancer.