HPN and colorectal carcinoma: Among them, only 3 of the serum markers showed a significant increase (p < 0.05) in mCRC, namely L1CAM (13.77 ± 1.439 ng/mL), CA9 (267.601 ± 35.162 pg/mL), and HPN (3.049 ± 0.172 ng/mL) as compared with primary CRC, respectively (7.619 ± 0.863 ng/mL; 174.567 ± 27.307 pg/mL; 2.427 ± 0.168 ng/mL) (Figure 1).