Recently, nectin-4 has been identified as a tumor marker in several types of carcinoma, including lung (9), breast (10), ovarian (11), esophageal (12), gastric (13), pancreatic (14), liver (15), colon (16), and bladder (17) cancers, and has been suggested to promote carcinogenesis (18–22). This evidence concerns the gene NECTIN4 and cancer.