BUB1 and urinary bladder carcinoma: To further explore the location of BUB1 expression, we conducted immunofluorescence staining of CK5, CK8 and BUB1 in human bladder cancer tissue, and the results demonstrated that the location of BUB1 expression was consistent with the location of CK5 expression, while the location of CK8 expression was opposite that of BUB1 expression (Fig. 1G).