C4A and cancer: The results showed that the high expression of six antigen genes, i.e., FUT1, AQP1, C4A, ART4, RHCE and DARC, was significantly associated with the earlier stage of eight types of cancers, i.e., KIRC, LIHC, LUAD, HNSC, PAAD, TGCT, KIRP and LUSC, and associated with the advanced stage of eight types cancers, i.e., BLCA, OV, BRCA, COAD, READ, SKCM, STAD and UCEC.