Uro-2 (CK20 + p53) is a primary antibody cocktail for the multiplex IHC identification of CK20 and p53 proteins in bladder. Studies have shown that in normal urothelium, the superficial umbrella cell layer shows reactivity for CK20 only; whereas, p53 nuclear staining is absent to focal. For urothelium with reactive atypia, particularly in cases with marked atypia, CK20 and p53 staining remain identical to those seen in normal urothelium. In cases of CIS, diffuse, strong cytoplasmic reactivity for CK20 and diffuse nuclear reactivity for p53 is observed throughout the urothelium. Most high-grade dysplasia stain with p53 when compared to low-grade dysplasia.