Aims: Uveal malignant melanoma is the most common intraocular tumor. The aim of this study was the analysis of bcl-2 oncoprotein expression in this tumor type. The melanomas were evaluated according to tumor location and patient age and sex. The relationship between bcl-2 expression and histological type, clinicopathologic stage and the presence of a set of predetermined morphological parameters was analyzed.
Methods: The study involved 39 patients with ocular melanomas treated with surgery alone between 1983 and 1997. Formalin-fixed, paraffin-embedded tissues were treated with anti-bcl-2 antibody (Dako No M0887). Immunolocalization of the bcl-2 oncoprotein was performed using the labeled streptavidin biotin (LSAB) method. bcl-2 expression in neoplastic cells was evaluated in a semiquantitative manner: lack of reactivity was defined as bcl-2 negative, reactivity present in less than 30% of cells as low bcl-2, and reactivity in more than 30% of cells as high bcl-2. The percentage of cells with a positive reaction was assessed independently by two pathologists, and the results were subjected to statistical analysis using Fischer's exact test.
Results and conclusion: No statistically significant correlation was found between the expression of bcl-2 oncoprotein and the clinicopathologic features analyzed. However, the high percentage of tumors with positive expression of this oncoprotein suggests that it plays a significant role in the biology of uveal melanoma.