PTGS2 and urinary bladder cancer: We observed that BCG-induced inflammation in human bladder cancer tissues involves the induction of COX2 and its product PGE2, associated with the EP4-mediated induction of the chemokines CCL22 and CXCL8, which attract myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) [51,111].