Abnormal nuclear expression of Pygopus‐2 in human primary hepatocellular carcinoma correlates with a poor prognosis

Aims Pygopus‐2 (Pygo2) is a critical element of the canonical Wnt/β‐catenin transcriptional complex. The aim of the present study was to investigate the expression patterns and clinicopathological significance of Pygo2 in human primary hepatocellular carcinoma ( HCC ). Methods and results Real‐time polymerase chain reaction ( PCR ) analysis of the m RNA levels of Pygo2 in 50 paired HCC cancer/adjacent non‐cancerous tissues showed that Pygo2 m RNA expression was significantly higher in cancerous tissues ( P  =   0.009). Immunohistochemical analysis showed that abnormal Pygo2 protein expression in HCC patients was associated with age ( P  =   0.025), tumour size ( P  =   0.005), intra‐ or extra‐hepatic metastasis ( P  =   0.029), vascular invasion ( P  =   0.026) and tumour differentiation ( P  =   0.004). Patients with normal Pygo2 protein expression showed a longer survival time ( P  =   0.031) and a higher 1‐year survival rate ( P  =   0.032) than those with abnormal Pygo2 expression. Cox's proportional hazard regression model showed that abnormal Pygo2 protein expression was a risk factor associated with the prognosis of HCC patients ( P  =   0.043). Conclusion To the best of our knowledge, this is the first report investigating Pygo2 expression patterns and their clinicopathological significance in HCC . Our findings suggest that Pygo2 may be an important predictor of poor outcome in HCC patients, and could serve as a novel biomarker for HCC .