Investigations of Macrophage and Dendritic Cell Markers in Uveal Melanoma

Abstract

Abstract: : Purpose:Wide variation in the level of macrophage infiltration has been reported in uveal melanoma. This study investigated levels of expression of macrophage and additionally dendritic cell markers in a series of primary posterior uveal melanomas. Methods:A series of 10 uveal melanoma biopsies were collected from theatre upon enucleation and either fixed immediately in formalin and embedded in paraffin wax, or established as short term cultures. Using immunohistochemistry, cultured cells or paraffin sections were analysed for a range of melanoma, dendritic cell and macrophage markers. Results:Expression of at least one known melanoma marker was detected in all samples. A high level of expression of macrophage markers was evident in both sections and cultured cells from the majority of tumours. In contrast, low expression of dendritic cell markers was restricted to a small number of tumours, and was absent in cultured cells. Double labeling using fluorescent-based immunohistochemistry confirmed macrophage and melanoma marker expression by the same cell. Conclusions:Wide variation of macrophage infiltration in uveal melanoma has been previously reported, and these differences may reflect the ability of some tumours to express macrophage-associated markers.

Keywords: melanoma • microscopy: light/fluorescence/immunohistochem • cell membrane/membrane specializations