Objective:To investigate effect and mechanism of mangiferin on regulation of M2-type macrophage polarization tar-geting MMP9 in pancreatic cancer.Methods:In vivo,therapeutic effect of mangiferin on pancreatic cancer was evaluated by drawing tumor growth curves and immunohistochemical staining.M2-type macrophages expression in pancreatic cancer was detected by immu-nofluorescence and ELISA.Effects of mangiferin on expression of MMP9 and downstream M2 macrophage polarization-related signaling pathways were detected by immunofluorescence,ELISA,Western blot and qRT-PCR.In vitro,MTT assay was utilized to detect effect of mangiferin on M2-type macrophage and therapeutic effect of mangiferin on pancreatic cancer.ELISA was used to detect effect of mangiferin on M2-type polarized macrophages.Effects of mangiferin on expression of MMP9 and its downstream signalling pathway were detected by immunofluorescence and Western blot.Results:Mangiferin had potential to inhibit growth of pancreatic cancer in mice pancreatic model,and could prevent expression of M2-polarized macrophages in pancreatic cancer in addition.At the same time,mangiferin could inhibit expression of MMP9 and downstream M2 macrophage polarization related signaling pathways in pancreatic cancer.Mangiferin inhibited proliferation of pancreatic cancer cells in a M2 type polarized macrophage-pancreas cancer cell co-culture model,inhibited macrophage M2 polarization,at the same time,expression of MMP9 and downstream M2 macrophage polarization related signaling pathway was inhibited.Conclusion:Mangiferin can inhibit macrophage M2 polarization by inhibiting MMP9 and its downstream signaling pathway,and play a role in pancreatic cancer therapy.