ERBB2 and breast cancer: The ERRα/PGC-1β complex then enhances the development of the ERBB2-positive tumor subtype and tamoxifen resistance in BC through transcriptional control of the ERRB2 amplicon.313 Moreover, the overexpression of miR-22-3p restrains the proliferation and migration of BC cells by directly targeting PGC-1β, ultimately regulating the PPARγ pathway in BC.314 However, miR-378 fulfils the metabolic shift that TCA cycle activity is reduced and the cells are less dependent on OXPHOS to fulfill their energy demands, which is achieved by suppressing the PGC-1β/ERRγ transcriptional pathway.315