Upregulation of ARHGAP9 is correlated with poor prognosis and immune infiltration in clear cell renal cell carcinoma.

Rho GTPase activating protein (ARHGAP) family genes play critical roles in the onset and progression of human cancer. Rho GTPase activating protein 9 (ARHGAP9) is upregulated in various tumors. However, far too little attention has been paid to the prognostic value of ARHGAP9 and correlation with immune infiltration in clear cell renal cell carcinoma (ccRCC). Our aim is to evaluate the prognostic significance of ARHGAP9 expression and its correlation with immune infiltration in ccRCC. Transcriptional expression profiles of ARHGAP9 between ccRCC tissues and normal tissues were downloaded from The Cancer Genome Atlas. The ARHGAP9 protein expression was assessed by the Clinical Proteomic Tumor Analysis Consortium. Receiver operating characteristic curve was used to differentiate ccRCC from adjacent normal tissues. The Kaplan-Meier method was conducted to assess the effect of ARHGAP9 on survival. Protein-protein interaction networks were constructed by the STRING. Functional enrichment analyses were performed using the "ClusterProfiler" package. The immune infiltration patterns were evaluated via the tumor immune estimation resource 2.0 and Tumor-Immune System Interaction Database. ARHGAP9 expression was substantially higher in ccRCC tissues than in adjacent normal tissues. Increased ARHGAP9 mRNA expression was shown to be linked to high TNM stage and lymph node metastases. The diagnostic value of ARHGAP9 gene expression data was assessed using receiver operating characteristic curve analysis. The survival analysis module of GEPIA2 and the Kaplan-Meier plotter both showed ccRCC patients with high-ARHGAP9 had a worse prognosis than those with low-ARHGAP9. Correlation analysis indicated ARHGAP9 mRNA expression was significantly correlated with tumor purity and immune infiltrates. These findings demonstrate that upregulated ARHGAP9 indicates poor prognosis and immune infiltration in ccRCC. The current findings suggest that ARHGAP9 can be an effective biomarker and potential therapeutic strategy for ccRCC.