C3 and neoplasm: Another study has also demonstrated that intracellular activation of complement C3 derived from tumor cells suppressed the infiltration and function of CD8+ cytotoxic T lymphocytes by promoting the accumulation and immunosuppressive activity of TAMs in a C3aR-dependent, rather than C5aR-dependent manner, resulting in activation of PI3Kγ signaling that mediates TAMs immunosuppressive activity [118].