PPARGC1A and cancer: To this end, we investigated enzymes involved in oxidative decarboxylation of pyruvate, Krebs cycle, fatty acid β-oxidation (and synthesis), and oxidative phosphorylation, as well as the parameters of mitochondrial dynamics—mitochondrial DNA copy number (MCN), peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), and mitochondrial structure—in breast tumor tissue and mammary adipose tissue from premenopausal women with benign or malignant tumors.