Histological and immunohistochemical study of hepatoblastoma: correlation with tumour behaviour and survival

Background: Hepatoblastoma (HB) has different histological subtypes, with varying prognosis. Though the survival has drastically improved, subsets of patients are not responsive to therapy. Therefore, it becomes important to determine the factors which affect the behaviour of the tumour. This study was aimed to look at the histopathological subtypes and compare with immunohistochemical (IHC) expression of CK19, beta-catenin and EpCAM and survival. Methods: This study included 55 cases of HB. IHC expression of CK19, beta-catenin and EpCAM were correlated with histological subtypes, tumour behaviour, response to chemotherapy and survival. Results: Most common epithelial subtype was fetal (43.2%) and mixed epithelial (54.8%) in pre- and post-chemotherapy groups respectively. Microvascular invasion (MVI) was present in 14/33 resected tumours. CK19 expression was seen in 54.2% and 72.2% of embryonal subtype, nuclear beta-catenin expression in 48.7% and 57.1% and EpCAM in 100% and 82.1% of tumours in pre- and post-chemotherapy groups, respectively. Fetal subtype had a lesser chance of MVI, recurrence, metastasis and death. Beta-catenin expression was associated with lower event free survival (EFS) and EpCAM with >= 50% viable tumour following chemotherapy (P = 0.04). Age at diagnosis <= 2 years, male sex, alpha-fetoprotein <10,000 IU/mL following chemotherapy, solitary tumour (P = 0.001), size <= 5 cm, pretreatment extent of disease (PRETEXT) I & II, mitosis <= 2/10 high power fields (hpf), viable tumour <50% (P = 0.04) and absent nuclear expression of beta-catenin, predicted a higher EFS rate. Conclusions: Beta-catenin expression is associated with lower EFS and EpCAM expression with tumour viability. Multifocality and viable tumour >= 50% were significant factors predicting lower EFS. These factors should be included in the prognostication of HBs.