Objective:To explore expression of VSIG4 in clear cell renal cell carcinoma(ccRCC)and its correlation with immune cells infiltration and prognosis.Methods:RNA-seq data of ccRCC and corresponding clinical data of patients were downloaded from The Cancer Genome Atlas(TCGA)database.Wilcoxon rank-sum test was used to analyze VSIG4 mRNA expression in ccRCC and normal renal tissues.Correlation between VSIG4 expression and clinicopathological parameters was analyzed by Wilcoxon rank-sum or Kruskal-Wallis rank-sum test.Kaplan-Meier method was used to analyze the correlation between VSIG4 expression and progno-sis of patients.Gene set enrichment analysis(GSEA)was used to explore the signaling pathway of VSIG4 in ccRCC.Correlation between VSIG4 level and tumor infiltrating immune cells was analyzed via CIBERSORT in R software.Western blotting was used to detect VSIG4 protein level in human renal epithelial cell line 293T,and human renal carcinoma cell line ACHN,A498,786-O and OS-RC-2.Results:Expression level of VSIG4 in ccRCC was significantly higher than that in normal tissues(P<0.05).VSIG4 expression was significantly correlated with the stages of distant metastasis and lymph node metastasis(P<0.05).Overall survival rate of patients with high VSIG4 expression was significantly lower than that of patients with low expression(P<0.05).GSEA enrichment analysis showed that VSIG4 was mainly enriched in apoptosis,chemokine signaling pathway,cell adhesion molecules and other signaling path-ways.VSIG4 expression was negatively correlated with M1 macrophages(r<0,P<0.05),while positively correlated with M2 macro-phages(r>0,P<0.05).Western blotting results showed that expression of VSIG4 in renal cell carcinoma cells was higher than that in normal renal cells.Conclusion:VSIG4 is highly expressed in ccRCC,and is negatively associated with prognosis,which may become a prognostic biomarker for ccRCC patients.