C9 and colorectal carcinoma: Among the differentially expressed proteins (DEPs), inter-alpha-trypsin inhibitor heavy chain (ITIH)3, leucine-rich alpha-2-glycoprotein (A2GL), C9, and lipopolysaccharide-binding protein (LBP) showed the highest levels in CRC patients, while apolipoprotein (APO) A4, acid labile subunit (ALS), and kallikrein B1 (KLKB1) showed the lowest levels compared to healthy controls.