Based on the available literature, CPZ (carboxypeptidase Z) is a metallopeptidase that demonstrates tissue-specific expression patterns and potential clinical utility as a diagnostic biomarker. CPZ exhibits cytoplasmic expression in normal hepatocytes, pancreatic islets, and gallbladder epithelium, but shows no expression in most other normal tissues 1. The protein demonstrates significant diagnostic value for hepatocellular carcinoma (HCC), with a positive expression rate of 90.8% in HCC cases compared to only 27.7% in intrahepatic cholangiocarcinoma and 0% in metastatic liver tumors 1. When used in combination with other markers like arginase-1 and hepatocyte paraffin antigen-1, CPZ achieves high diagnostic accuracy with an AUC of 0.939 for HCC diagnosis 1. As an individual marker, CPZ shows superior performance compared to established hepatocyte markers, particularly in poorly differentiated HCC cases 1. Genetic polymorphisms in the CPZ gene (rs3796725 and rs3796727) have been investigated for neuroblastoma susceptibility, though no significant associations were found in Chinese populations 2. The available evidence is limited regarding CPZ's specific enzymatic mechanisms and broader physiological functions, requiring additional research to fully characterize this metallopeptidase.