C9 and colorectal carcinoma: Differential expression analysis of the FT fraction between CRC and healthy control groups showed that 4 proteins (HSP90B1, C4A, C1qC, and PBP) were up-regulated and 1 protein (FN) was down-regulated in non-metastatic CRC, while 5 proteins (LRG, S100A8, C4A, C9, and C4B) were up-regulated and 2 proteins (APOC3 and FN) were down-regulated in metastatic CRC groups, respectively (Fig. 1B and 1C).