Our findings pointed out that (a) ERRα plays a role in vitamin D metabolism and sensitivity in breast cancer, (b) the ERRα/VDR axis is at the crossroads of estrogen signaling activation, and (c) the simultaneous overexpression of ERRα, VDR, and CYP24A1 is correlated with poor prognosis in basal‐like breast cancer. The gene discussed is VDR; the disease is breast cancer.