CPQ (carboxypeptidase Q) is a metalloenzyme with dipeptidase activity that appears to play important roles in both normal physiological processes and disease pathogenesis. Based on current evidence, CPQ functions as a carboxypeptidase involved in peptide metabolism and may contribute to thyroid hormone processing from thyroglobulin precursors. The protein exhibits metallodipeptidase activity and is involved in proteolysis and peptide catabolic processes, with cellular localization in the cytoplasm, Golgi apparatus, endoplasmic reticulum, and lysosomes. In disease contexts, CPQ has emerged as a potential biomarker and therapeutic target. CPQ was identified as one of seven high-risk genes associated with cancer-associated fibroblasts in glioma progression, where it may contribute to poor patient prognosis 1. Additionally, CPQ protein levels were significantly elevated in serum samples from patients with chr8 antibody-mediated rejection (CAMR) following kidney transplantation compared to controls 2. CPQ was also found to be upregulated in hepatocellular carcinoma tissues compared to normal liver tissue 3. However, the specific molecular mechanisms by which CPQ contributes to these pathological processes remain largely undefined, and further research is needed to elucidate its precise functional roles in both normal physiology and disease progression.