CHI3L1 and melanoma: Recent studies from our laboratory also demonstrated that IL-13 is not the sole ligand for IL-13Rα2 and that chitinase 3-like-1 (Chi3l1, also called YKL-40 in man and BRP-39 in the mouse) binds to, signals and regulates oxidant injury, apoptosis, pyroptosis, inflammasome activation, pathogen responses, melanoma metastasis and TGF-β1 elaboration via IL-13Rα2 (ref. 13).