Firstly, serum CEA levels in HCC patients (11.18 ± 2.61 ng/mL) were significantly higher than those in healthy controls (1.06 ± 0.13 ng/mL), particularly in cases with distant metastases (13.72 ± 2.88 ng/mL) [34]. Here, CEACAM5 is linked to hepatocellular carcinoma.