Nectin-4 (Nectin Cell Adhesion Molecule 4) is a member of the nectin family of immunoglobulin-like cell adhesion molecules. It is highly expressed during embryonic development but shows limited expression in most normal adult tissues. Nectin-4 is overexpressed in a variety of solid tumors, including bladder, breast, lung, pancreatic and ovarian cancers, and has been associated with tumor growth, invasion and metastasis. Studies have shown that Nectin-4 contributes to tumor progression through multiple signaling pathways, including PI3K/Akt signaling. Due to its restricted expression in normal tissues and elevated expression in malignant tumors, Nectin-4 has emerged as an attractive therapeutic target for cancer diagnosis and treatment.