Abstract
Purpose: :
Uveal melanoma is the most common ocular tumor and about 50% of patients die of their disease, due to hematogenous metastatic spread. This fatal outcome still occurs despite apparently successful treatment of the primary ocular tumor. Endocan, also called endothelial cell specific molecule 1 (or ESM-1) is a biomarker of neoangiogenesis which has been recognized as being one of the most significant molecular signatures of a bad prognosis in VEGF-driven cancers such kidney, brain and lung cancers. By microarray, independant teams have recently described the potential of endocan to be a biomarker of tips cells in the retina in animal models of diabetic retinopathy.
Methods: :
Our study included 49 patients who undergone surgery for uveal melanoma between 1989 and 2009 at the University Hospital of Lille (France). Immunohistochemistry was performed using the monoclonal anti-human endocan antibody, clone MEP 08 (Lunginnov, Lille, France). Endocan expression was confirmed by biochemical techniques such as Western blot and ELISA that used different couples of monoclonal antibodies against human endocan.
Results: :
In this study, we demonstrated for the first time, that endocan is expressed by tumors vessels in 77 % of the studied population with uveal melanoma (38 patients). Endocan was detected intracellularly in the vessel inside the tumors but never detected in area without tumors. Interestingly, we described that tumor cells within uveal melanoma clearly expressed endocan. This expression by non-endothelial cells has been observed in other type of tumors and seems to correlate with bad prognosis and metastasis. Furthermore, the expression of endocan by tumor cells was more intense in perivascular area leading the question of the role of endocan in tumor progression.
Conclusions: :
In this preliminary study, we demonstrated for the first time that endocan is expressed in both vascular and tumor compartments in uveal melanoma. Endocan have been recognized as one of the most significant molecular signatures of a bad prognosis in several types of cancer including renal and lung cancer. The urge of new biomarkers to identify patients before occurrence of metastases raise the relevance to drive further studies to evaluate endocan in uveal melanoma as prognostic biomarker and help to develop new treatments in the future.
Keywords: melanoma • immunohistochemistry