Immunoexpression of cell cycle biomarkers in neuroblastoma samples and its correlation with prognostic factors

Abstract

Introduction: It is widely known that the expression levels of molecules involved in apoptosis regulation and cell proliferation have prognostic value in patients with neuroblastomas. Objective: To determine the expression of Ki67, B-cell lymphoma 2 (BCL-2), phosphatase and tensin homolog (PTEN), BCL-2 associated protein X (BAX) and caspase-8 proteins in neuroblastomas and to propose new prognostic biomarkers that could enable a better classification of risk groups. Material and methods: Formalin fixed paraffin embedded neuroblastoma samples (n = 23) were arranged into tissue microarray blocks and analyzed by immunohistochemistry. The patients were classified according to clinical and pathological prognostic factors (age, site, presence or absence of bone-marrow infiltration, poorly or well differentiated ganglioneuroblastoma, Schwannian stroma rich or poor, favorable or unfavorable Shimada histology, and presence or absence of MYCN oncogene amplification) and clinical course (with or without fatal outcome, with or without relapses/residual lesion). Results: Twelve patients were female; nine children were over 18 months old; nine had extra-abdominal tumors; nine had tumors with unfavorable histology. Fifteen patients underwent bone-marrow biopsy and four were positive for metastasis. Nine patients progressed to fatal outcome. Conclusion: Ki67 immunoexpression was lower in cases of Schwannian-stroma rich neuroblastomas (p = 0.018) and higher in poorly differentiated cases (p = 0.013). PTEN was less positive in stroma rich neuroblastomas (p = 0.024). Caspase-8 was more immunopositive in cases of negative bone marrow infiltration (p = 0.035). Therefore, these biomarkers could be applied to discriminate groups with poor prognosis.