Abstract
Abstract: :
Purpose: CSE1L/CAS is a recently described protein associated with proliferation and apoptosis. It has first been found in breast cancer but has now been demonstrated in several other cancers and tissues as well. In this study, we have investigated human retinal pigment epithelium (RPE) in subretinal neovascular membranes (SRNVs) and in enucleation specimens for the presence and distribution of CSE1L/CAS. Methods: Paraffin sections of subretinal membranes from 4 patients ( 71 to 80 years) and 8 human eyes (5 to 79 years) were labeled with an antibody against CSE1L/CAS. The SRNVs were additionally labeled with Ki67 as a marker for proliferative activity. The eyes had been removed for either choroidal melanoma, end–stage glaucoma or phthisis. Immunoreactivity (IR) was visualized using AEC. Results: Only little IR in the RPE was detected in eyes with glaucoma and with apparently normal RPE while in 3 of the 4 SRNVs obvious albeit inhomogenuous labeling was observed in the RPE as well as in cells forming the fibrovascular tissue. CSE1L/CAS IR corresponded to the intensity of Ki67 staining; one SRNV did not reveal significant labeling with either Ki67 or anti–CSE1L/CAS. – In eyes harbouring a choroidal melanoma, notable IR was seen in the RPE overlying and surrounding the tumor while RPE away from the tumor was hardly stained. The melanoma cells themselves also revealed moderate labeling particularly in the periphery. In addition, very intense labeling was also observed in an epiretinal membrane present in one of the melanoma eyes. Conclusions: CSE1L/CAS is potentially present in human RPE and can be observed particularly in association with SRNVs and choroidal melanoma. Its precise function, however, remains as yet unclear. Possibly intraocular tumors can upregulate its expression, and one might speculate on its implication for retinal proliferative disease such as age–related macular degeneration and proliferative vitreo–retinopathy.
Keywords: retinal pigment epithelium • immunohistochemistry • pathology: human