C3 and cancer: Seven of these components, significantly more abundant in cancer NAF, were associated with the initial triggering (complement factor B; immunoglobulin heavy constant gamma 3; complement component 3) and regulation (complement decay-accelerating factor; component C9; complement factor B; immunoglobulin heavy constant gamma 3; complement component 3; C4b-binding protein alpha chain; component C8 alpha chain) of complement, by activation of complement component C3 and component C5 (complement component 3 upregulated).