Prognostic value of <i>BAP1</i> protein expression in uveal melanoma

BACKGROUND: Uveal melanoma is the most common malignant ocular tumor in adults. It carries a high risk of metastatic spread and death. Typical clinical and morphological signs fail to provide accurate disease prognosis. Thus, investigations of molecular markers such as BAP1 expression are warranted to improve survival prediction and optimize treatment strategies. AIM: The work aimed to determine the prognostic value of the histological type of uveal melanoma and BAP1 expression for survival of patients. METHODS: We performed a retrospective analysis of the data of 68 patients with uveal melanoma who received curative treatment. A standard procedure was used for the morphological examination of enucleated eyes. BAP1 protein expression was evaluated using immunohistochemistry. Survival was analyzed using Kaplan–Meyer methods and a Cox proportional hazard model. RESULTS: Median survival in patients with homo- or heterogeneous (focal, mosaic) loss of BAP1 expression was 48 months, whereas patients with homogeneous BAP1 expression of variable degree (mild to severe) did not achieve the median by the end of follow-up. The log-rank test showed statistically significant differences between these groups (χ2=4.344; p=0.037). Mortality risk for patients with homo- or heterogeneous loss of BAP1 expression was 2.6 times higher (HR=2.602, 95% confidence interval: 0.573–0.96). However, mortality risk for patients with epithelioid cell and mixed tumor types was only 1.27 times higher than for patients with spindle cell cancer (HR=1.265, 95% confidence interval: 1.062–2.846). CONCLUSION: The study highlights the importance of using molecular genetic methods, including immunohistochemistry of BAP1, to predict disease outcomes more accurately.