C3 and cancer: Bioinformatic analysis of the prognostic impact of the complement genes allowed to classify cancers in four groups: protective complement (concomitant occurrence of favorable prognosis associated with high expression of complement genes), protective C3 (favorable prognosis found only for high C3 expression but not for the other genes), aggressive complement (concomitant occurrence of poor prognosis, associated with high expression of complement genes) and uncertain significance of complement (when no particular pattern is observed) [3] (Figure 2).