Cellular and stromal microenvironment of metastatic choroidal melanoma

Abstract

Introduction. Choroidal melanoma is a malignant neoplasm of the eye’s vascular membrane. Prognosing and preventing metastasis are the main objectives of ocular oncology, aimed at maximizing the relapse-free survival of patients. Our goal was to determine the features of the cellular and stromal microenvironment of metastatic choroidal melanoma based on the immunohistochemical characteristics of surgical specimens. Materials and methods. We conducted a retrospective analysis of surgical specimens of cases of choroidal melanoma obtained from 2013 to 2017 and divided them into 2 study groups: group 1 included cases of choroidal melanoma without distant metastases (n=25) and group 2 involved cases of choroidal melanoma with distant liver metastases (n=18). The study was conducted using medical records analysis, histological, immunohistochemical, morphometric, and statistical research methods. Results. In group 2, the level of cells expressing CD4 markers – 138.5 (99.8;153.3), CD68 – 137 (99,5;173,8) and CD56 [5 (3;6)] prevailed significantly. The indicators of CD4 lymphocytes >95 and CD68 macro-phages >104 were found to allow the prediction of the appearance of distant choroidal melanoma metastases with the sensitivity of 83.3% and 72.2% and specificity of 76% and 76%, respectively. The indicators of the volume density of blood vessels in the tumor <3.9 (with a sensitivity of 77.8% and specificity of 64%) were of the same prognostic value. Conclusion. Metastatic choroidal melanoma is characterized by features of the cellular and stromal microen-vironment. Quantitative indicators of CD4 lymphocytes and CD68-macrophages and the volume density of blood vessels in the tumor have prognostic value with high sensitivity and specificity for predicting distant tumor metastasis. Keywords: choroidal melanoma, lymphocytes, macrophages, metastases, tumor blood vessels