Abstract
Ependymomas are common pediatric brain tumors that originate from the ependyma and characterized by poor prognosis due to frequent recurrence. However, the current WHO grading system fails to accurately predict outcome. In a retrospective study, we analyzed 54 intracranial pediatric ependymomas and found a significantly higher overall survival in supratentorial cases when compared to infratentorial tumors. Next we performed region-specific immunohistochemical analysis of the ependyma in neonatal and adult ependyma from the central canal of spinal cord to the choroid plexus of lateral ventricles for components of cell-cell junctions including cadherins, claudins and occludin. We found robust claudin-5 expression in the choroid plexus epithelia but not in other compartments of the ependyma. Ultrastructural studies demonstrated distinct regional differences in cell-cell junction organization. Surprisingly, we found that 9 out of 20 supratentorial but not infratentorial ependymomas expressed high levels of the brain endothelial tight junction component claudin-5 in tumor cells. Importantly, we observed an increased overall survival in claudin-5 expressing supratentorial ependymoma. Our data indicates that claudin-5 expressing ependymomas may follow a distinct course of disease. The assessment of claudin-5 expression in ependymoma has the potential to become a useful prognostic marker in this pediatric malignancy.
Highlights
Ependymomas are the third most common central nervous system (CNS) malignancies in children [1]
It is obvious that the course of the disease is different in pediatric and adult cases as it is reflected by a number of clinicopathological parameters
There was no significant difference in the grade distribution between the supratentorial and infratentorial group (Table 1)
Summary
Ependymomas are the third most common central nervous system (CNS) malignancies in children [1]. One major concern is the fact that most of the clinical studies on ependymoma included pediatric and adult cases and statistical analysis was often performed in these combined cohorts. For instance in adult ependymomas supratentorial location is indicator of a worse prognosis while the limited number of studies with pediatric cases does not support this observation [9, 11]. It has been demonstrated in a large cohort of pediatric and adult cases that potential histological prognosticators have a localization dependent role [20]. A recent study suggested that anaplastic morphology has a prognostic significance in pediatric infratentorial ependymomas [21]
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