Expression of immature (Nestin) and mature (NF & GFAP) retinal cell markers in retinoblastoma to clarify the origin of retinoblastoma

Abstract

Despite numerous pathological studies, the origins of retinoblastomas are still controversial .Aim: of this study was to clarify which factors are expressed in retinoblastoma cells and to give insights into the cell origin of retinoblastomas. Materials and methods: eleven patients with retinoblastoma (7 males & 4 females) patients were diagnosed in the Eye tumor Unit, Ophthalmic Department, Ain Shams University; they were divided into 5 groups according to International Classification of Retinoblastoma. Sections were examined histopathologically and immunostained by mouse monoclonal antibodies against Nestin, GFAP and NF for identification of undifferentiated stem cells, mature glial cells and mature neurons. Results: histopathologic findings in the examined samples revealed that 6 cases were poorly differentiated and 5 cases were well differentiated. Both Nestin and GFAP expressions were detected in the stromal cells not in the tumor cells, possibly representing muller cells and reactive stromal astrocytes respectively, in contrast, in all samples neurofilaments were expressed in the cytoplasm of the most retinoblastoma cells. In conclusion, the results of this study support that retinoblastomas are derived from mature neural cells and not originate from cancer stem cell(s).