C3aR is ubiquitously expressed in many tissues like the bone marrow,28 brain,29 heart30 and skin.31 Interestingly, C3aR blockade has been shown to suppress C3 activation in mouse lungs, suggesting a dependence on C3aR in C3a production.32 Our results showed that the C3aR antagonist decreased cancer cell proliferation and migration, compared with the control without C3a treatment. The gene discussed is C3AR1; the disease is cancer.