TNF and malnutrition: Causes of reduced muscle mass induced by cancer include malnutrition, physical inactivity, altered metabolism and increased proinflammatory cytokines such as Tumor Necrosis Factor- α (TNF-α), Interleukin-1-β (IL1-β) and Interferon-γ (IFN-γ), that seem to upregolate muscle degradation as detected in muscular biopsies of cancer patient.