High SPATA18 Expression and its Diagnostic and Prognostic Value in Clear Cell Renal Cell Carcinoma

BACKGROUND SPATA18 (spermatogenesis-associated 18, also called Mieap) encodes a protein that can induce lysosome-like organelles within mitochondria, which plays an important role in tumor growth. We measured the expression of SPATA18 in ccRCC, and assessed its diagnostic and prognostic clinical value in patients with clear cell renal cell carcinoma (ccRCC). MATERIAL AND METHODS We analyzed SPATA18 expression using data from the TCGA-KIRC cohort, GEO database, and UALCAN database. Immunohistochemistry was carried out to verify the expression in the ccRCC patients. The diagnostic value of SPATA18expression was evaluated by a receiver operating characteristic (ROC) curve. The correlation between clinical characteristics and SPATA18 expression was calculated by chi-square test. The prognostic value of SPATA18 expression was assessed by Kaplan-Meier analysis and Cox analysis. We conducted gene set enrichment analysis (GSEA) using TCGA database. RESULTS SPATA18 gene exhibited a higher expression in ccRCC tissues than in normal tissues. SPATA18 showed a substantial diagnostic value in ccRCC. SPATA18 expression was correlated with histological grade, clinical stage, T classification, and distant metastasis of ccRCC. Furthermore, high SPATA18 expression was associated with favorable overall survival. Multivariate analysis showed that SPATA18 was an independent risk factor for ccRCC. Gene set enrichment analysis (GSEA) showed that B cell receptors, WNT targets, extracellular matrix, oxidative phosphorylation, calcium metabolism, iron uptake and transport, potassium channels, and insulin receptor were differently enriched in the phenotype that was negatively correlated with SPATA18. CONCLUSIONS Our study indicated that high SPATA18 expression in ccRCC was associated with a good prognosis, and it could be a positive prognostic biomarker for ccRCC.