Starting from the observation that some of the exercise-based interventions and exercise mimetic effects in tumor-bearing animals are based on the ability to stimulate the expression and the activity of the master regulator of mitochondrial biogenesis PGC-1α, several studies have focused on the impact of this transcriptional coactivator on muscle phenotype, both in health and in wasting conditions, including cancer cachexia. The gene discussed is PPARGC1A; the disease is cancer.