Nectin-4 is detected in low levels in certain normal human tissues (bladder, breast, stomach, esophagus, skin and salivary glands); however, it is upregulated mostly in the cell membrane and cytoplasm of human bladder, breast, ovarian, lung and pancreatic cancer tissues, with bladder and breast cancer tissues having the highest expression levels [7]. Here, NECTIN4 is linked to breast cancer.