CD38 and plasma cell myeloma: CD38, a single-chain type II transmembrane glycoprotein, is significantly and consistently expressed on the surface of multiple myeloma cells.[35] It serves various functions, including receptor-mediated adhesion, cell signaling, and regulation of cyclase and hydrolase activities.[36] The high expression of CD38 on multiple myeloma cell membranes has made it an ideal therapeutic target for interventions in multiple myeloma.[17] Consequently, the development of novel treatment drugs targeting CD38 has become a hot topic in RRMM management.