MSTN and cancer: Indeed, novel molecules have recently been identified as triggers of muscle wasting during cancer, at least at the preclinical level, such as leukemia inhibitory factor (LIF) [23], TNF-related weak inducer of apoptosis (TWEAK) [24], the negative regulator of muscle mass myostatin [25,26], High Mobility Group Box 1 (HMGB1) [13], tumor-derived parathyroid hormone-related protein [27], growth differentiation factor 15 (GDF-15) [28], and microRNAs from the tumor itself [29,30,31].