Prognostic Value of the Immunohistochemical Expression of Serine and Arginine-Rich Splicing Factor 1 (SRSF1) in Uveal Melanoma: A Clinico-Pathological and Immunohistochemical Study on a Series of 85 Cases

Uveal melanoma (UM) is the most frequent primary ocular malignancy of adults; it exhibits an almost invariably poor prognosis with onset of liver metastases within 10-15 years after the diagnosis. Serine and arginine-rich splicing factor 1 (SRSF1) is an RNA-binding protein with proto-oncogene functions, including stimulation of angiogenesis, cell migration and cell growth; regarding the complex regulation of tumor angiogenesis, it has been suggested that SRSF1 regulates the alternative splicing of vascular endothelial growth factor-alpha, promoting the formation of its pro-angiogenic isoform. The immunohistochemical expression of SRSF1 on a series of 85 primary UMs, including 39 metastasizing and 46 non-metastasizing cases, was investigated; to clarify the potential pathogenetic role of SRSF1 in this tumor and its effect on angiogenesis, we correlated our immunohistochemical findings with the clinico-pathological features, the prognostic data and blood vascular microvessel density (MVD) findings of the cases from our series. Cases with higher immunohistochemical expression of SRSF1 also had higher MVD, higher metastatic potential and shorter metastasis-free survival; conversely, cases with lower SRSF1 immunoexpression showed lower MVD, lower metastatic risk and longer metastasis-free survival times. Our results suggested that SRSF1 has a negative prognostic role and a pro-angiogenic function in UM.