WNK2 and central nervous system cancer: Caffeine metabolism has been reported to participate in the regulation of signaling pathways associated with cellular apoptosis of glioma, including activation of cathepsin B, mitogen-activated protein kinase, and caspase-3.[52,53] In addition, the metabolites of the caffeine metabolite pathway may regulate the activity, cellular cycle, and proliferation of glioma negatively.[54] The present study identified for the first time the potential association between xanthine, 3-methylxanthine, theobromine, paraxanthine, and the pathogenesis of AA.