CXCR2 and clear cell renal carcinoma: As Table 3 shown, high-expression of CXCR2 was significantly related to a poorer OS for patients with laryngeal squamous cell carcinoma (HR = 2.93, 95% CI = 1.10–7.75, p = 0.03) in the subgroup analysis by tumor type, astrocytic tumors (HR = 1.86, 95% CI = 1.05–3.31, p = 0.03), lung cancer (HR = 1.56, 95% CI = 1.22–2.01, p = 0.0005; I2 = 0%, p = 0.98), pancreatic ductal carcinoma (HR = 5.51, 95% CI = 1.38–22.0, p = 0.02), clear-cell renal cell carcinoma (HR = 2.20, 95% CI = 1.26–3.25, p = 0.004) and hepatocellular carcinoma (HR = 1.74, 95% CI = 1.17–2.59, p = 0.007), respectively.