NAMPT and gastric cancer: USP22 can regulate SIRT1 through the c-myc/ Nicotinamide phosphoribosyltransferase (NAMPT) pathway, thereby affecting the Forkhead Box O1 (FOXO1) and Yes-associated protein (YAP) signaling pathways, which are respectively related to GC cells apoptosis and metastasis (Liu et al., 2019).