Svetlana Cherepanoff, Enisa Hasic, Mark C Gillies
To describe S100 expression in the retinalpigment epithelium (RPE) of normal human eyes andin eyes with both tumour and non-tumour pathology.
S100 immunohistochemistry was per-formed using polyclonal rabbit anti-human S100antibody and the Bond Polymer Red Detection kitfrom Leica with the Leica Bond II automatedimmunohistochemistry protocol. A total of 14 humaneyes were included in the study. RPE S100 expressionwas examined in six normal control eyes, two evis-cerations, two pthisical eyes, one enucleationfor retinoblastoma, one enucleation for choroidalmelanoma and two enucleations for chronic retinal detachment.
RPE in normal control eyes showed patchyweak cytoplasmic S100 staining. S100 was morestongly expressed in both the cytoplasm and nucleus ofall pathological eyes, except in retinoblastoma. Expres-sion was not uniform. Eyes with long term retinaldetachment showed the strongest nuclear and cyto-plasmic S100 staining.
S100 may be a novel marker of RPEabnormality, particularly in eyes with long term retinaldetachment.