Abstract
Purpose :
Uveal melanoma (UM) is the most common ocular tumor in adults and despite effective local treatment, overall outcome has not improved. Moreover, once metastases occur, the outcome is poor. Consequently, detection of novel biomarkers has the potential to aid the development of therapeutic options and is useful to better understand disease progression. Nestin is a neural stem cell marker previously found to be associated with reduced survival in cutaneous melanoma. The purpose of this study is to characterize Nestin expression in UM and its utility as a prognostic marker.
Methods :
In total, 46 UM enucleated eyes were examined, 24 of which had corresponding survival data. One sample was removed due to complete tumor necrosis. Slides were retrieved from the MUHC-McGill University Ocular Pathology Laboratory. Fully-automated immunohistochemistry using an anti-Nestin polyclonal antibody was performed. Tumors were classified according to cell type (spindle or epithelioid). Slides were graded based on intensity (0=negative, 1=positive, 2=strong positive) and extent of staining (focal=1, diffuse=2). A score was obtained for each tumor by adding extension and intensity grades. Statistical analysis was performed using Mann-Whitney test to assess group differences according to cell type, presence of metastases and metastasis-free survival.
Results :
Immunohistochemical staining of ciliary body was used as an internal control. All 45 tumors were positive for Nestin. Staining intensity was not correlated with survival (P=0.523), and staining extent did not correlate with cell type (P=0.224). Within a given tumor, the intensity of Nestin staining was always higher (2) in epithelioid cells compared to the spindle cells (1).
Conclusions :
To the best of our knowledge, this is the first study characterizing Nestin expression in UM. Due to the presence of Nestin in all cases, it should be included as part of the immunohistochemical panel for UM diagnosis. Although no correlation between Nestin staining and survival was found in our cohort, the increased positivity in epithelioid cells follows the same pattern as seen in cutaneous melanoma in which increased expression correlated with poor prognosis. Further studies with a larger patient cohort is necessary to confirm our results.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.