## Des-Gamma-Carboxyprothrombin (DCP) in HCC **Key Point:** Des-gamma-carboxyprothrombin (also called PIVKA-II — Protein Induced by Vitamin K Absence) is an abnormal prothrombin produced by hepatocellular carcinoma cells due to impaired vitamin K-dependent carboxylation. **High-Yield:** DCP is MORE specific for HCC than AFP, particularly in early-stage disease and in AFP-negative HCC cases. It represents a post-translational modification defect, not a new protein synthesis. ### Mechanism Normal hepatocytes synthesize prothrombin with gamma-carboxyglutamic acid residues (vitamin K-dependent). HCC cells produce prothrombin lacking these residues, creating the abnormal "des-gamma" form. ### Clinical Relevance | Feature | AFP | DCP | |---------|-----|-----| | Sensitivity in HCC | 60–70% | 40–50% | | Specificity | Lower (benign liver disease) | Higher (more HCC-specific) | | Best use | Screening; prognostic | Diagnosis confirmation; early detection | | Elevation in benign disease | Common (cirrhosis, hepatitis) | Rare | **Clinical Pearl:** DCP + AFP together improve diagnostic accuracy for HCC. DCP elevation in the absence of AFP suggests early HCC or AFP-negative tumors. ### Why DCP is the Answer DCP is the tumor marker most directly linked to abnormal post-translational modification (impaired vitamin K carboxylation) and is the most specific for HCC among the options given. 
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