GP73, a resident Golgi glycoprotein, is a novel serum marker for hepatocellular carcinoma

Golgi protein-73 (GP73) is up-regulated in hepatocellular carcinoma (HCC). The aims of this study were to determine if GP73 is detected in the serum, and to establish the sensitivity and specificity of serum GP73 for diagnosing HCC.Serum GP73 was detected by immunoblots and quantified by densitometric analysis.A total of 352 patients were studied. Serum GP73 levels were significantly higher in patients with HCC compared to those with cirrhosis (P < 0.001). GP73 had a sensitivity of 69% and a specificity of 75% at the optimal cutoff point of 10 relative units, with an area under the receiver operating curve of 0.79 vs. 0.61 for AFP (P = 0.001). GP73 levels had significantly higher sensitivity (62%) than AFP (25%) for diagnosing early HCC (P < 0.0001). Moreover, GP73 levels were elevated in the serum of 57% (32/56) of individuals with HCC who had serum AFP levels less than 20ng/ml.Higher levels of GP73 can be found in the serum of patients with HCC than of those without. GP73 was better than AFP for the diagnosis of early HCC. Further validation studies are needed to confirm the role of GP73 in the early detection of HCC.