KRT7 and neoplasm: However, the immunohistochemical staining showed results similar to the preoperative biopsy: the tumor cells were uniformly negative for CK(AE1/AE3) (Fig. 3b), CK7, CK20, P63 (while the remaining superficial urothelial cells were positive), focally positive for EMA, and positive for vimentin and P53.