E-Cadherin Expression in Renal Cell Carcinoma according to the Mainz Classification

Lee, Ju Han; Cho, Hyun Deuk; Lee, Dale; Won, Nam Hee

Abstract

According to the Mainz classification, renal cell carcinoma (RCC) consists of three subtypes: each has characteristic genetic alterations within the chromosomal or mitochondrial DNA. The three subtypes are: clear cell type, chromophil type, and chromophobe type. E-cadherin is a Ca++-dependent adhesion molecule which plays a major role in the maintenance of intercellular adhesion in epithelial tissues. In a normal kidney, E-cadherin is expressed in the distal tubule and the collecting duct, but not in the proximal tubule. We reclassified 110 cases of RCC according to mainz classification. Immunohistochemical staining for E-cadherin was done on twenty eight cases of RCC, including 18 cases of clear cell type, four cases of chromophil type, and six cases of chromophobe type. The results were as follows: 1) of the 110 cases of RCC, 96 cases (87.3%) were of clear cell type, four cases (3.6%) of chromophil type, and ten cases (9.1%) of chromophobe type, 2) there was no significant correlation between the nuclear grade and clinical stage according to each subtype, 3) E-cadherin expression showed a strong positive reaction along the cell membranes in all six cases of chromophobe type. The differential expression of E-cadherin in RCC may suggest that the chromophobe type may have different biologic characteristics from other types of RCC.