C5 and nonpapillary renal cell carcinoma: Moreover, we show that an increased production of PTX3 within the renal tumour may modulate the immunoflogosis in the ccRCC microenvironment, by partially activating the classical pathway of complement system (C1q) and releasing pro-angiogenic factors (C3a, C5a), but inhibiting the complement-mediated cellular lysis due to local up-regulation of CD59.