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