PIWIL1 and hepatocellular carcinoma: Neutralization of C3 attenuated the induction of p38 MAPK signaling activation (Fig. 6d), as well as IL10 production (Fig. 6e) in MDSCs, treated with the conditioned medium, indicating that C3 may play a critical role in enhancing the immunosuppressive activity of MDSCs in PIWIL1-overexpressing HCC.