PPARGC1A and neoplasm: In this regard, the expression of the peroxisome proliferator-activated receptor-γ (PPAR-γ) coactivator-1α (PGC-1α), the master regulator of mitochondrial biogenesis and oxidative metabolism, was shown to be reduced in the skeletal muscle of tumor-bearing mice [78], although this is not a constant finding [73, 79].