Nectin-4/ poliovirus Receptor-like 4 (PVRL4) is a type I transmembrane glycoprotein belonging to the immunoglobulin superfamily that promotes intercellular adhesion by acting as a major component of adhesion junctions. The extracellular domain of Nectin-4 consists of one Ig variable region (V) and two Ig constant regions (C) , which mediate binding to measles virus and adjacent cells through trans-heterophile interactions with Nectin-1. Unlike other members of the connectin family, which are widely expressed in adult tissues, human Nectin-4 expression is largely limited to the blastoderm. Studies have shown that Nectin-4 is overexpressed in cells from a variety of human solid tumors, including pancreatic, breast, lung, and ovarian cancers. The expression pattern of Nectin-4 in normal tissues is limited, so NECTIN-4 can be used as a novel therapeutic target for various human tumors.