Immunohistochemical properties of ocular adenomas, adenocarcinomas and medulloepitheliomas

Abstract

Ocular medulloepitheliomas, adenomas and adenocarcinomas share a common phenotype and originate from the cells of the ciliary epithelium. This can make it very difficult to differentiate between these tumors histopathologically. Therefore, this study focused on identifying a combination of immunological markers that might be used in the diagnosis of these tumors. These markers included AE1/AE3, CK7, CK20, and telomerase reverse transcriptase (TERT).

Routine immunohistochemical staining was performed on twenty-one whole globes diagnosed with one of these tumors. The tumors that immunostained for TERT showed increasing immunoreactivity as the tumor types increased in aggressiveness. None of the tumor types were immunopositive for CK7. CK20 immunostaining was found in the adenomas but not in the adenocarcinomas or medulloepitheiomas. AE1/AE3 expression was present more consistently in the adenocarcinomas and less frequently in the adenomas. There was no AE1/AE3 expression in the medulloepitheliomas confirming their mesenchymal origin. Furthermore, CK20 and TERT show inverse expression patterns, i.e., TERT increases in expression and CK20 decreases in expression with increasing aggressiveness. These results may be important diagnostic and prognostic indicators for these tumors.