The study investigates the role of tumor-derived lactic acid in the polarization of tumor-associated macrophages (TAMs) and its impact on tumor growth. Lactic acid, produced by tumor cells as a byproduct of glycolysis, is shown to induce the expression of vascular endothelial growth factor (VEGF) and the M2-like polarization of TAMs through the stabilization of hypoxia-inducible factor 1a (HIF1a). The lactate-induced expression of arginase 1 (Arg1) by TAMs is found to play a crucial role in tumor growth. The findings suggest that lactic acid acts as a signaling molecule, promoting TAM polarization and enhancing tumor growth. The study also demonstrates that this process is independent of interleukin 4 (IL-4) and interleukin 13 (IL-13) signaling, indicating an alternative pathway for TAM polarization. Overall, the research highlights the importance of lactic acid in the communication between tumor cells and TAMs, contributing to tumor maintenance and growth.The study investigates the role of tumor-derived lactic acid in the polarization of tumor-associated macrophages (TAMs) and its impact on tumor growth. Lactic acid, produced by tumor cells as a byproduct of glycolysis, is shown to induce the expression of vascular endothelial growth factor (VEGF) and the M2-like polarization of TAMs through the stabilization of hypoxia-inducible factor 1a (HIF1a). The lactate-induced expression of arginase 1 (Arg1) by TAMs is found to play a crucial role in tumor growth. The findings suggest that lactic acid acts as a signaling molecule, promoting TAM polarization and enhancing tumor growth. The study also demonstrates that this process is independent of interleukin 4 (IL-4) and interleukin 13 (IL-13) signaling, indicating an alternative pathway for TAM polarization. Overall, the research highlights the importance of lactic acid in the communication between tumor cells and TAMs, contributing to tumor maintenance and growth.