Immunohistochemical expression of beta-catenin in hepatoblastoma and its clinical significance

Background: Primary hepatic malignancies account for 0.5-2% of all solid tumours in childhood. Hepatoblastoma, a rare embryonic tumour in the general population, represents the most frequent primary hepatic malignancy in the paediatric age group, with an incidence of one new case per million under 15 years of age, median age at diagnosis being 1 year. Aberrant activation of the Wnt/beta-catenin signalling pathway is likely to result in tumorigenesis of hepatoblastoma. The nuclear and intra-cytoplasmic accumulations of beta-catenin correlate with the likely prognosis of the disease. Nuclear expression of beta catenin is associated with a shorter survival, higher stage, and seen in embryonal/undifferentiated types. Aim: To study the expression of beta-catenin in hepatoblastoma by immunohistochemistry and correlate it with the tumour histology and survival outcome. Materials & Methods: This is a retrospective study of 11 children over a period of 5 years with the diagnosis of hepatoblastoma. These children underwent partial hepatectomy or liver transplantation at the Department of Paediatric Surgery. The clinical, histological and survival data were collected. Immunohistochemical analysis with beta-catenin was done and analysed. Results: Mean birth weight of the children was 2.75kg.63.6% had an epithelial type of histology.Beta catenin expression by IHC was studied in 11 cases and found to be positive in 4 cases. Nuclear positivity was noted in 2/4 cases of embryonal type and Cytoplasmic and membranous positivity was seen in the other 2/4 cases. Normal liver showed a membranous pattern of positivity in one case. Negative staining was seen in 6 out of 11 cases. Conclusion: Beta catenin is considered to be an useful tool for assessing the prognosis of patients with hepatoblastoma and its expression is associated with a poor survival outcome. There are no validated biomarkers for prognosis so far. However, larger studies incorporating molecular profiling is warranted to establish prognostic factors for planning effective treatment strategies.