PTGS2 and neoplasm: In general, M1 macrophages function in the recruitment of Th1 cells, resistance against microbial pathogens, and regulation of tumor cell metabolism through innate and adaptive immune responses by producing proinflammatory cytokines, such as interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and cyclooxygenase-2 (COX-2) [73].