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Neuroblastoma is the most common extracranial solid malignant tumor observed during childhood. Although these tumors can sometimes regress spontaneously or respond well to treatment in infants, genetic alterations that influence apoptosis can, in some cases, confer resistance to chemotherapy or result in relapses and adversely affect prognosis for these patients. The aim of this study was to correlate immunohistochemical expression of the protein quiescin sulfhydryl oxidase 1 (QSOX1) in samples obtained from untreated neuroblastomas with the patients’ clinical and pathological prognostic factors and clinical course. Neuroblastoma samples (n=23) obtained from histology blocks were arrayed into tissue microarrays and analysed by immunohistochemistry. The cases were classified according to the following clinical and pathological prognostic factors: age at diagnosis greater or less than/equal to 18 months; location of the lesion at diagnosis (abdominal or extra-abdominal); presence or absence of bone-marrow infiltration; tumor differentiation (well or poorly differentiated); Shimada histopathologic classification (favourable or unfavourable); state of the tumor extracellular matrix (Schwannian-stroma rich or poor); amplification of the MYCN oncogene; and clinical course (dead or alive with or without relapses/residual lesions). Twelve of the cases were female, 9 children were over 18 months old, 9 cases presented with extra-abdominal tumors and 9 cases exhibited tumors with unfavourable histologies. Fifteen patients underwent bone-marrow biopsy, and 4 of these were positive for metastasis. Nine patients died. The higher immunohistochemical expression of QSOX1 was more common in well-differentiated samples (P=0.029), in stroma-rich samples (P=0.029) and in samples from patients with a high prevalence of relapses/residual disease. The functions of QSOX1 include extracellular matrix maturation and the induction of apoptosis. Therefore, QSOX1 may be involved in neuroblastoma differentiation and regression and may thus function as a biomarker for identifying risk groups for this neoplasm.

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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.