C5AR1 and neoplasm: Therefore, we implemented the subgroup analysis based on sample size and the results showed that for sample size≥100, higher C5aR expression was more prone to develop advanced tumor stage (OR = 1.88, 95%CI: 1.30–2.71, P = 0.001) with a low heterogeneity (I2 = 39.5%, P = 0.116) (Fig. S1).