CA9 and neoplasm: Based on some antigens or receptors that are highly expressed on the surface of tumor cells, such as CD19, carbonic anhydrase IX (CA IX), glycyrrhetinic acid (GA) receptors, asialoglycoprotein receptor (ASGPR), integrin α5 (ITGA5) receptor and folate acid (FA) receptor, some researchers have designed and constructed a variety of NCTD-loaded actively targeted nano-drug delivery systems to increase the concentration of NCTD in target cells, thereby enhancing its efficacy and reducing its toxicity and side effects (Table 3).