Citation:
Date Published:
2015 Mar 5Abstract:
PURPOSE: To compare immunohistochemical and genetic overlaps and differences between intraocular medulloepitheliomas and embryonal tumors with multilayered rosettes of the brain. DESIGN: Retrospective histopathologic, immunohistochemical and genetic analysis of 20 intraocular medulloepitheliomas. METHODS: 1) Review of clinical data and hematoxylin and eosin stained sections with 2) immunohistochemical staining of paraffin sections using a polyclonal antibody against the protein LIN28A, and 3) FISH testing for the amplification of the genetic locus 19q13.42 involving the C19MC cluster of miRNA. Ten retinoblastomas served as controls and to determine the specificity of these biomarkers for intraocular medulloepitheliomas. RESULTS: Nineteen of the 20 intraocular medulloepitheliomas were either diffusely or focally LIN28A positive (weak, moderate or strong). The most intense positivity correlated with aggressive behavior such as intraocular tissue invasion or extraocular extension. None of the cases studied by fluorescence in situ hybridization (FISH) harbored an amplicon for C19MC. The ten retinoblastomas were LIN28A and C19MC negative. CONCLUSION: LIN28A has a putative role in oncogenesis and is found only in embryonic cells and malignancies. Intraocular medulloepitheliomas and embryonal tumors with multilayered rosettes of the brain both display LIN28A positivity. Only the latter, however, display amplification of the 19q13.42 locus involving C19MC, implying that other causative factors are at play in intraocular medulloepitheliomas. More aggressive tumor behavior within the eye can be partially predicted by LIN28A staining intensity.