Nuclear localization of β-catenin is an important prognostic factor in hepatoblastoma

In this study, mutational and immunohistochemical analyses of β catenin were performed in 30 hepatoblastomas, to assess the prevalence of alterations of the Wnt pathway with respect to clinicopathological parameters and survival. Four missense mutations of β-catenin (13.3%) were detected and there was strong immunoreactivity for β-catenin in the cytoplasm and/or the nucleus in 97% of hepatoblastomas. Nuclear and cytoplasmic staining was demonstrated in 19 of 30 tumours (63%), while ten revealed only cytoplasmic staining. Statistically, this nuclear β-catenin staining was significantly higher in the embryonal (Fisher exact test; p = 0.00393) or undifferentiated type (p = 0.00156) of hepatoblastoma than in the fetal type, but there was no difference between clinical stages I and II and clinical stages III and IV (p = 0.175). Cumulative survival curves showed that nuclear β-catenin staining (generalized Wilcoxon test; p = 0.0088), undifferentiated histological type (p = 0.0305), and clinical stages III and IV (p = 0.0107) were significantly correlated with shorter survival time in these patients. Moreover, Cox multivariate analysis provides evidence that nuclear β-catenin staining is the most important prognostic factor for survival (p = 0.0090). It is therefore concluded that immunohistochemical analysis of β-catenin might be a useful clinical tool for estimating the prognosis for patients with hepatoblastoma.