RET and sarcopenia: Mechanistically, GDF15 could induce weight loss via the GDNF family receptor alpha-like (GFRAL)-Ret proto-oncogene (RET) signaling complex in neurons in the brainstem [22,23,24,25], and the antibody-mediated inhibition of GDF15–GFRAL activity has been shown to reverse excessive lipid oxidation and prevent sarcopenia in cancer-bearing mice [26].