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 QSOX1 (quiescin
sulfhydryl oxidase 1) 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.