Aminopeptidase N (APN/CD13) is closely related to the growth of cancers and is suggested as a suitable target for anti-cancer therapy. Recently, a research group used the “one-bead-one-compound” (OBOC) approach on a microarray device to scren out a novel affinity peptide LN (YEVGHRC). It was found that LN could specifically recognize and bind to APN; Moreover, LN-functionalized liposomes (LN-LS) could achieve efficient nano-encapsulated drug delivery under APN-overexpressing tumor conditions in vitro and in vivo, providing a new strategy for APN-positive tumor diagnosis and therapy. Biomater Sci. 2017 Feb 28;5(3):417-421.