Apoptotic protein expression, glycogen content, DNA ploidy and cell proliferation in hepatoblastoma subtyping and their role in prognostication

Abstract

Purpose: To evaluate Bcl-xL, Bax, PCNA, cytokeratin 19 (CK-19), glycogen content and DNA ploidy expression in hepatoblastoma (HB) and their prognostic value.

Methods: This retrospective study on 26 cases of HB involved DNA ploidy estimations separately for various subtypes on histological sections using image cytometry of Feulgen-stained smears. Glycogen content, PCNA, CK-19, Bax and Bcl-xL expression on tissue sections were evaluated. THE outcome on follow-up (mean 86 months) and Kaplan-Meier survival analysis were performed.

Results: Fetal areas were diploid (84%); embryonal areas were aneuploid (89.47%) (p < 0.001). PCNA labeling index was low in fetal (10.82%) and high in embryonal areas (59.85%) (p = 0.03). CK-19 was negative in fetal, but focally positive in embryonal areas. Bax was negative in fetal (80%) and positive in embryonal areas (88.23%) (p < 0.001); Bcl-xL was more frequently positive in fetal (90%) than embryonal areas (52.94%) (p = 0.02). Fetal cells were rich in glycogen. Kaplan-Meier survival analysis showed good initial radiological response to chemotherapy (p = 0.009), glycogen content (p = 0.0137) and DNA diploid cases (p = 0.0429) were associated with good outcome on univariate analysis. Histology typing (p = 0.085), Bcl-xL (p = 0.689), Bax (p = 0.27), CK-19 (p = 0.281), PCNA (p = 0.689), age (p = 0.24), sex (p = 0.5661), stage (p = 0.24) and α-fetoprotein levels (p = 0.49) were unrelated to outcome. Multivariate analysis showed glycogen content to be the most statistically significant variable (0.024).

Conclusion: Fetal and embryonal areas show different staining patterns for PCNA, Bax and Bcl-xL. DNA ploidy and glycogen content are significant prognostic variables.