Diagnostic Accuracy of Golgi Protein 73 (GP73) for Liver Fibrosis Staging in Metabolic Dysfunction-Associated...

Background/Objectives: Golgi protein 73 (GP73) is a transmembrane protein expressed by epithelial cells of the bile duct in the normal liver. High serum levels of GP73 have been detected in patients with acute or chronic liver diseases, MASLD, and its measurement has been suggested as a potential biomarker for liver fibrosis staging. We evaluated the utility of GP73 in the diagnosis of MASLD, MASH, and for liver fibrosis staging. Methods: We performed a literature scoping review to map the current evidence about the accuracy of GP73 in patients with MASLD. We searched in Medline and EMBASE for English studies reporting an AUC value of GP73 in diagnosing MASLD and MASH and evaluating GP73 for fibrosis staging. A narrative synthesis of the evidence was conducted. Moreover, we performed an observational study including 84 patients with MASLD, of which 60 were biopsy-confirmed MASH, and different liver fibrosis stages, and 15 healthy controls. Serum GP73 levels were determined using a chemiluminescent assay and reported as mean and standard deviation (SD). Sensitivity (SE), specificity (SP), the area under the receiver operating characteristic (AUROC) curve, and the optimal cut-off value were calculated. Data were considered statistically significant when p < 0.05. Results: Available studies evaluating GP73 in MASLD reported the ability to discriminate MASH from simple steatosis and distinguish patients at different fibrotic stages, but the evidence is still scarce. Our experimental study showed that the serum levels of GP73 were 30 ± 12 ng/mL in MASLD and 32 ± 12 ng/mL in MASH patients and were statistically higher than those of the control group (19 ± 30 ng/mL), increasing from liver fibrosis stage F0 to F4. GP73 levels were significantly higher in patients with significant and advanced fibrosis than controls and no significant fibrosis (p > 0.05). ROC analysis demonstrated that serum GP73 had a good diagnostic potential for MASLD (AUROC 0.85; SE 90%; SP 73%), MASH (AUROC 0.75; SE 82%; SP64%), and significant fibrosis (AUROC 0.7; SE 56%; SP 79%) and was better than other biomarkers for chronic liver diseases. Conclusions: Serum GP73 could support clinicians in the evaluation of patients with MASH and significant fibrosis.