MIB1 and urinary bladder carcinoma: In this article, we studied the features of muscle-invasive bladder carcinomas in comparison to non-invasive bladder carcinomas in Egyptian patients at the level of histopathology, and immunohistochemical staining of p16, p53, and MIB-1 (Ki-67) to assess their role in bladder cancer pathology of MIBC versus NMIBC.