Expression and Subcellular Distribution of Membrane-Organizing Extension Spike Protein (Moesin/ MSN) are Associated with Epithelial-Mesenchymal Transition in Clear Cell Renal Cell Carcinoma

Background:Clear cell renal cell carcinoma (ccRCC) is an aggressive urological malignancy. The aggressive potential of ccRCC is attributed to epithelial-mesechymal transition, which acquire the neoplastic cells more invasive properties. Membrane-Organizing Extension Spike Protein (Moesin/ MSN) plays an important role in controlling cellular morphology and motility. Aim:Evaluation of moesin expression in ccRCC and determine its cellular distribution, and then correlate its expression with certain clinicopathological variables.Methods:Archived formalin-fixed, paraffin-embedded ccRCC tissue blocks of 55 patients were obtained and sectioned. From each tissue block; 2 tissue sections were stained by hematoxylin and eosin (H&E) stain and anti-moesin immunohistochemical antibody. Results:Less differentiated cases of ccRCC with high WHO/ISUP grades were significantly associated with male sex (p= 0.023), presence of perirenal fat invasion (p< 0.001) and advanced tumor stages (p= 0.003).Moesin showed membranous localization in all enrolled cases. Membranous moesin expression was associated with high WHO/ISUP grades (p= 0.004), advanced tumor stages (p< 0.001), capsular and perirenal fat invasion (p= 0.001& p< 0.001) and presence of lymph nodes invasion (p< 0.001).Cytoplasmic redistribution of moesin was detected in 30 cases. Cytoplasmic moesin was correlated with capsular and perirenal fat invasion (p= 0.033& p= 0.001), tumors with high WHO/ISUP grades (p< 0.001), advanced tumor stages (p< 0.001) and presence of nodal metastasis (p= 0.002).Conclusion:Membranous overexpression of moesin and its cytoplasmic redistribution were detected in aggressive and less differentiated cases of clear cell renal cell carcinoma.