C5AR1 and nonpapillary renal cell carcinoma: As shown in Table 2, univariate analysis reconfirmed the strong significance between C5a and OS (HR 1.818, 95% CI 1.142–2.894, P = 0.012), and multivariate analysis verified the independence of C5a in predicting ccRCC patients’ OS (HR 1.753, 95% CI 1.068–2.878, P = 0.026), just like TNM stage (P < 0.001), Fuhrman grade (P = 0.002), Necrosis (P = 0.023), and ECOG-PS (P < 0.001).