Circular RNAs as prognostic and diagnostic biomarkers in renal cell carcinoma

BACKGROUND: Circular RNAs (circRNAs) play pivotal roles in proliferation, apoptosis, migration, and invasion of renal cell carcinoma (RCC) cells. This study is aimed to systematically summarize the current evidence regarding the clinical implications of circRNAs in RCC patients. METHODS: A systematic search in PubMed, Embase, and Web of Science was performed until January 1, 2022. The correlation between the expression of circRNAs and clinicopathological, prognostic, and diagnostic features of RCC was evaluated using the meta‐analysis. RESULTS: Ultimately, 41 studies with 3485 RCC patients were included in this study: 26 studies for clinicopathological features, 31 studies for prognosis, and eight studies for diagnosis. Altered expression of circRNAs was significantly associated with clinicopathological characteristics of RCC, including tumor size, tumor stage, lymph node metastasis, distant metastasis, and TNM stage. The tumor promoter circRNAs were associated with reduced overall survival (OS) (Hazard Ratio (HR) = 1.98, 95% confidence interval [CI] 1.68–2.34) and disease/progression/recurrence‐free survival (DFS/PFS/RFS) (HR = 2.34, 95% CI 1.85–2.97). Contrarily, the tumor suppressor circRNAs were linked with better OS (HR = 0.49, 95% CI 0.40–0.60) and DFS/PFS/RFS (HR = 0.40, 95% CI 0.28–0.59). The pooled sensitivity and specificity of circRNAs for RCC diagnosis in tissue samples were both 0.84. These results in fluid samples (serum and urine) were 0.78 and 0.69, respectively. CONCLUSION: CircRNAs can serve as promising diagnostic and prognostic biomarkers for RCC.