Cilnicopathological Significance of E-Cadherin Expression in Renal Cell Carcinoma / 대한비뇨기과학회지

PURPOSE: E-cadherin(E-CD) is a family of Ca++-dependent intercellular adhesion molecules, plays essential roles in organogenesis and in the maintenance of normal structure and function. Decreased expression of E-CD correlates with tumor aggressiveness, advanced stage and metastasis. In renal cell carcinoma(RCC), however, this correlation is not well established and prevalence of negative expression of E-CD is higher than in other carcinomas. We focused our interest on E-CD expression in RCC and its clinicopathological implications. MATERIALS AND METHODS: Retrospectively, we reviewed 34 cases with RCC that were reclassified according to Mainz classification. Tumor stage, grade were determined according to the Robson method and Fuhrmann`s grading system. We detected E-CD expression in RCC by immunohistochemical staining and investigated the relationship between E-CD expression and clinicopathological features including prognosis. RESULTS: Thirty four cases of RCC were consisted of 21 cases(61%) of non-papillary clear cell type, 2 cases(6%) of chromophil type, 3 cases(9%) of spindle cell type and 8 cases(24%) of chromophobe type by Mainz classification. Especially, E-CD expression showed a strong positive reaction along the cell membranes in all 8 cases of chromophobe type. Our immunohistochemical study of E-CD expression in 34 RCC specimens showed 73% of positive expression and 27% of negative expression. Absence of E-CD expression was correlated with the high tumor stage and grade( stage & grade 3 or 4. p<0.05 in chi-squar test). All of metastatic cases showed a negative expression of E-CD. CONCLUSIONS: The differential expression of E-cadherin in renal cell carcinomas suggest that the tumor cell origin and differentiation. Especially, chromophobe cell type may have different biologic characteristics from other types of renal cell carcinoma. In this study, E-CD expression was seemed to be lost in RCC with a high stage and grade. In addition, preserved E-CD expression was associated with better prognosis than reduced E-CD expression.

Histopathology and Mainz Classification of Renal Cell Tumors: A Histogenetic Study and DNA Content Analysis

The Mainz classification for renal cell tumors was introduced in 1986 and it's utility has been reported in several histogenetic and genetic studies of renal cell tumors. We present a study of 127 cases of renal cell tumors with clinicopathologic correlation, DNA content analysis, and histogenesis studied by histochemical and immunohistochemical staining. The 127 renal cell tumors classified by the Mainz classification were 87 clear cell, 17 chromophilic, 13 chromophobe and 3 sarcomatoid renal cell carcinomas, 5 oncocytomas and 2 adenomas. These subtypes showed significant correlation not with age, sex, Robson's stage, DNA ploidy or tumor recurrence but with nuclear grade (p=0.001) and tumor size (p=0.001). Hall's colloidal iron (p=0.002) and carbonic anhydrase II (p=0.013) stains, representing the origin of distal nephron especially of collecting duct, were significantly correlated with specific subtypes of renal cell tumors, especially chromophobe cell renal carcinoma. This study demonstrates that the Mainz classification suggests several morphologically different subtypes and variants of renal cell tumors and that some of them may have originated from the distal nephron, particularly from the collecting duct.