CXCL8 and renal cell carcinoma: Overall, six papers met the predefined inclusion criteria, with final analyses demonstrating that high IL-8 levels significantly correlate with worse prognosis in RCC, with a statistically shorter PFS (hazard ratio [HR]: 1.27, 95% confidence interval [CI]: 1.01-1.59; P = 0.037) and statistically shorter OS (HR: 1.85, 95% CI: 1.21-2.84; P = .001).