STAT3 and urothelial carcinoma: It has been reported that multiple signal transduction pathway inhibitors, including the mitogen‐activated protein kinase, fibroblast growth factor receptor inhibitors, and chemotherapy drugs, can induce activation of STAT3 survival signaling pathway, leading to drug resistance.34, 35 Our study revealed that PARP and bcl‐2 apoptotic signaling pathway may be involved in the cytotoxicity of B17 niclosamide derivative for urological cancer, especially the urothelial carcinoma cells.