Immunohistochemical analysis of prame expression as a prognostic factor in uveal melanoma patients

Abstract

The study objective is to analyze the prognostic significance of PRAME protein expression in patients with uveal melanoma using immunohistochemical assay.Materials and methods. A total of 30 patients with uveal melanoma were examined and treated. The average age of patients at the time of treatment was 51.3 ± 11.8 years. In all cases, enucleation was performed according to the indications. A routine clinical-morphological, molecular-genetic, and immunohistochemical assay study was performed (n = 29). The immunohistochemical study was performed using antibodies to PRAME (clone 6H8, dilution 1: 50). The median follow-up period was 86.3 ± 2.9 months.Results. Of the 29 samples studied, staining was determined in 16, which was 55.2 %. Weak intensity of 1+ staining (from 10 to 20 % of tumor cells) was detected in 7 uveal melanoma samples, medium intensity of 2+ (from 10 to 20 % of tumor cells) – also in 7, and strong intensity of 3+ (30 % of tumor cells) – in 2 tumor samples. When assessing the seven-year survival, the cumulative survival rate in the group without PRAME expression was 0.857, while in the group with PRAME expression it was significantly lower and amounted to 0.357 (p = 0.0001). The PRAME protein expression was significantly correlated with the epithelioid cell type of the tumor (p = 0.041) and with the total and partial monosomy of chromosome 3 (p = 0.013).Conclusion. This paper presents the world’s first study of the prognostic significance of PRAME protein expression by immunohistochemical analysis in patients with uveal melanoma. A significant association of PRAME-positive patients with an unfavorable vital prognosis was shown.

Keywords

• uveal melanoma
• immunohistochemistry assay
• expression
• prame