Endoglin Expression in Uveal Melanoma: Implication for Prognosis

Abstract

Abstract: : Purpose:Endoglin/CD105 is a membrane protein involved in the TGF–ß receptor signalling pathway and has been associated with angiogenesis and prognosis in several malignancies. The aim of this study was to investigate the expression and prognostic value of endoglin in uveal melanomas. Methods:Paraffin sections from 35 clinicopathologically well characterized cases of primary uveal melanomas were stained for Ki–67, von Willebrand factor and endoglin. In 16 cases metastatic disease led to death. The mean follow–up of the non–metastasized cases was 10.6 years (9–13 years). The immunohistological specimens were evaluated by three independent observers who were masked to the follow–up of patients. Statistical analyses included Kaplan–Meier survival curves and the fitting of Log–Rank and Wilcoxon Test models. Results:Immunohistochemistry with vWF confirmed that all examined specimens were vascularized. Expression of Ki–67 could be found in 26 (74%) of the samples. Moderate to high expression of endoglin was found in 13 cases (37%). Kaplan–Meier analysis showed a significant association (P < 0.001) between enhanced endoglin expression and death due to metastatic uveal melanoma. Conclusion:This study demonstrates for the first time that endoglin, a marker for angiogenesis, is expressed in uveal melanomas. Furthermore, the data suggest a relevant prognostic role of the angiogenic activity in uveal melanomas.

Keywords: melanoma • oncology • immunohistochemistry