C5AR1 and neoplasm: Studies clear that C1q can participate in the recruitment of peripheral blood monocytes, suppress macrophage inflammation and inflammasome activation (Benoit et al., 2012), and C5a can activate the NF-κB pathway through the C5aR1 receptor and promote the M2 like polarization of TAMs, thereby inhibiting the tumor immune response and promoting tumor progression (Piao et al., 2018).