Epithelial to mesenchymal transition in clear cell renal cell carcinoma with rhabdoid features

Aims: The aims of this study were to investigate the association of renal cell carcinoma (RCC) displaying rhabdoid features and morphologically mesenchymal characteristics with epithelial to mesenchymal transition (EMT), and to clarify the expression of EMT markers. Methods: We investigated the expression of EMT markers (E-cadherin, vimentin, Snail, Slug, ZEB1, ZEB2 and Twist1) using immunohistochemistry, Western blotting and real-time polymerase chain reaction in 18 cases of clear cell RCC (ccRCC) with rhabdoid features and 74 ccRCC cases with Fuhrman grade 1-3 (G1 to G3). Results: In ccRCCs with rhabdoid features, low E-cadherin and high vimentin expression were found. In G1 to G3 ccRCCs, low E-cadherin expression and high expression of vimentin, ZEB1 and ZEB2 were found. There was no significant difference in the immunoexpression of E-cadherin and vimentin between the two ccRCC groups. Conclusions: The rhabdoid features may histologically and biologically be associated with EMT in ccRCC. There is a possibility that in G1 to G3 ccRCCs showing epithelial structures, other cell-cell adhesion mechanisms apart from E-cadherin adhesion may continue to work, and that ccRCC with rhabdoid features may be caused by an inactivation or loss of these mechanisms.