摘要Objective miR-34c-3p is down-regulated in nasopharyngeal carcinoma(NPC).The biological role of miR-34c-3p in NPC and its underlying mechanisms are unknown and were explored in this study.Methods Flow cytometry and immunohistochemical staining were employed to detect cluster of differentiation 86(CD86)and cluster of differentiation 206(CD206)expression;quantitative real-time polymerase chain reaction(qRT-PCR)and western blotting were employed to examine mRNA expression and protein levels;cell counting kit-8(CCK8)and transwell assays were employed to assess cell proliferation,migration,and invasion;and hematoxylin-eosin(HE)staining was employed to assess pathological changes in tumor tissues.Results Our results revealed that the miR-34c-3p mimic markedly inhibited M2 polarization of macrophages by targeting SLC7A11,and M2 macrophages transfected with the miR-34c-3p mimic inhibited the proliferation,migration,and invasion of NPC cells.The in vivo experiments further confirmed that miR-34c-3p mimics blocked tumor growth and reduced inflammatory infiltration in tumor tissues.Conclusion This study provides novel insights into the pathogenesis of NPC and a new treatment strategy.