MSTN and cancer: In addition to pro-inflammatory cytokines, two particular members of the TGF-β family have been particularly explored in cancer cachexia: myostatin (MSTN) and Activin A. MSTN clearly represents one of the most potent negative regulator of muscle growth and is known to act through its receptor ActRIIB and the subsequent activation of the SMAD2/SMAD3 cascade (Rodriguez et al., 2014).