Retinoblastoma is an aggressive eye cancer of infancy and childhood. Identification of high-risk features for tumor spread and a possible prognostic marker during histopathological examination of enucleated eyes is crucial to guard further treatment and follow-up plan. CD24 is reported as a poor prognostic marker in many types of malignant tumors.Objective
The aim of the present study was to evaluate CD24 immunohistochemical expression in retinoblastoma and its correlation with clinicopathological features, to explore the possible prognostic value of CD24 in these tumors.Materials and methods
This retrospective study included 33, formalin-fixed, paraffin-embedded tissue sections from primarily enucleated eyes with retinoblastoma. Immunohistochemical staining for CD24 was performed. The staining pattern was recorded, and both extent and intensity of staining were evaluated semiquantitatively. An additive score (AS) for CD24 expression was calculated for each tumor. CD24 expression was subsequently correlated with various clinicopathological features.Results
At least focal, weak CD24 staining was noted in all studied cases of retinoblastomas. The staining pattern was membranous-cytoplasmic in 60.6% of cases and membranous in the remaining 39.4%. In differentiated areas of tumors, Homer–Wright rosettes were found to have no CD24 expression, whereas Flexner–Wintersteiner rosettes showed variable apical staining. CD24 staining intensity and extent were significantly related to retinoblastoma risk groups with more strong and diffuse CD24 expression among high-risk retinoblastomas compared with low-risk tumors (P=0.033 and 0.048, respectively). The extraocular retinoblastomas demonstrated more diffuse CD24 staining compared with the intraocular tumors (P=0.029).Conclusion
CD24 is overexpressed in retinoblastoma, and immunohistochemically determined CD24 expression is a potential marker of prognosis in this disease.