STAT3 and cancer: 1. In bladder cancer: Binds to CSF2Rα to activate the STAT3 pathway and upregulates the expression of the anti-apoptotic protein Bcl-2;2. Promotes the accumulation of myeloid-derived suppressor cells (MDSCs) and inhibits the function of effector T cells;3. Enhances the activity of cancer-associated fibroblasts (CAFs) and promotes matrix remodeling