Decreased expression of zinc-alpha2-glycoprotein in hepatocellular carcinoma associates with poor prognosis.

Background: Zinc-alpha2-glycoprotein (AZGP1, ZAG) was recently demonstrated to be an important factor in tumor carcinogenesis. However, AZGP1 expression in hepatocellular carcinoma (HCC) and its significance remain largely unknown.
Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to determine mRNA level of AZGP1 in 20 paired fresh HCC tissues. Clinical and pathological data of 246 HCC patients were collected. Tissue-microarray-based immunohistochemistry (IHC) was performed to examine AZGP1 expression in HCC samples. Relationship between AZGP1 expression and clinicopathological features was analyzed by Chi-square test, Kaplan-Meier analysis and Cox proportional hazards regression model.
Results: AZGP1 expression was significantly lower in 80.0% (16/20) of tumorous tissues than that in the corresponding adjacent nontumorous liver tissues (P < 0.001). Consistently, IHC data revealed that decreased expression of AZGP1 was present in 80.1% (197/246) of HCC patient tissues (P < 0.001). Furthermore, AZGP1 expression in HCC significantly associated with several clinicopathological parameters, including serum AFP level (P = 0.013), liver cirrhosis (P = 0.002) and tumor differentiation (P = 0.025). Moreover, HCC patients with high AZGP1 expression survived longer, with better overall survival (P = 0.006) and disease-free survival (P = 0.025). In addition, low AZGP1 expression associated with worse relapse-free survival (P = 0.046) and distant metastatic progression-free survival (P = 0.036).
Conclusion: AZGP1 was downregulated in HCC and could be served as a promising prognostic marker for HCC patients.