Proteomic analysis of aqueous humor in retinoblastoma: a preliminary approach

Purpose Compare the basic protein composition of the aqueous humor from retinoblastoma (RTB) patients with aqueous humor from patients with cataract who served as controls. Methods The study was carried out on 18 hospitalized RTB patients, who had undergone ocular enucleation (Reese-Ellsworth stage V or ABC classification group E RB), and 10 cataract patients. Five out of 18 RTB patients presented with associated secondary glaucoma and 5 out of 13 with no secondary glaucoma received chemotherapeutical treatment with Melphalan. The total protein concentration and electrophoresis pattern (SDS PAGE) of the aqueous humor was analysed. Results The aqueous humor from RTB patients had significantly higher total protein concentrations than controls (p<0.01); patients with secondary glaucoma presented with the highest total protein concentrations, and they were significantly different from controls (p<0.05), while those treated with Melphalan presented a 70% decreasing in protein concentration and, in respect to all non-treated patients, were significantly different (p<0.01). Besides, the protein content of controls was not significantly different from treated patients. The SDS PAGE pattern of RTB patients was very different from controls; yet, after chemotherapeutical treatment, patterns were similar. Conclusion This study represents a preliminary step towards a more accurate 2DE pattern, which will be combined with mass spectrometry analysis to clarify the potential role of specific proteins in tumor development and progression; although this results suggest that aqueous humor protein pattern in RTB is characteristic, several aspects of the study are still under investigation.