ESRRA and breast cancer: Of note, in line with the pivotal role of PGC‐1α as a key regulator of metabolic reprogramming in advanced cancer [38, 39], PGC‐1α emerged as a central mediator in the directed network connecting VDR and ESRRA, thus supporting the notion that a PGC‐1α /ERRα‐containing complex drives a program that alters vitamin D metabolism in advanced breast cancer.