Analysis of Bcl-2 protein expression in choroidal melanomas

Background: Bcl-2 protooncogene alterations are involved in tumorigenesis and may have prognostic ramifications. Aims: To investigate normal ocular structures and choroidal melanoma for: ( 1) Bcl-2 protein expression ( semiquantitative staining values: SI, staining intensity; PP, percentage of positive cells; and IRS, immunoreactivity score) and ( 2) any associations between the staining values and clinicopathological features in these lesions. Materials/Methods: Bcl-2 protein expression was analysed in 24 choroidal melanomas using immunoperoxidase staining methods. Results: Bcl-2 protein expression was seen in corneal epithelium, lens epithelium, the ciliary body, and retinal cells. In these structures, the mean (SEM) values were: 1.1 (0.1), 1.6 (0.3), 1.1 ( 0.1), and 2.3 ( 0.3), respectively, for SI; 1.6 ( 0.2), 1.7 ( 0.1), 1.7 ( 0.2), and 1.7 ( 0.2) for PP, respectively; and 1.9 (0.4), 2.7 (0.5), 1.9 ( 0.1), and 4.0 (0.8), respectively, for IRS. Based on Bcl-2 immunoreactivity, the lesions were divided into two groups. The first group comprised 12 tumours with Bcl-2 expression. Bcl-2 expression was significantly higher in this group compared with normal ocular structures (1.5 ( 0.1) v 2.8 ( 0.2), 1.7 ( 0.1) v 3.5 ( 0.1), and 2.6 ( 0.3) v 9.3 (0.9) for mean ( SEM) SI, PP, and IRS scores, respectively; p = 0.00). The second group comprised 12 tumours lacking Bcl-2 protein expression. There was no significant correlation between Bcl-2 protein expression and most of the clinicopathological features of these lesions. Conclusions: Bcl-2 protein expression is altered in choroidal melanomas.