NECTIN4 and cancer: In a study investigating the expression of Nectin-4 in normal human tissues and various cancer tissues, immunohistochemical analysis of 294 normal tissue specimens representing 36 human organs showed homogeneous weak-to-moderate staining mainly in human skin keratinocytes, skin appendages (sweat glands and hair follicles), transitional epithelium of the bladder, salivary glands (ducts), esophagus, breast, and stomach tissue [26].