CD44 is an independent prognostic factor in conventional renal cell carcinomas

Purpose: CD44 is a transmembrane glycoprotein involved in cell-cell and cel l-matrix interactions. De novo expression of CD44 and its variant isoforms has been associated with aggressive behavior in various tumors. Since few d ata are available concerning the role of CD44 in the biological behavior of locally confined renal tumors, we analyzed the expression of CD44 in a lar ge set of conventional renal cell carcinomas to determine its prognostic va lue in association with other clinicopathologic variables. Materials and Methods: Ninety-one patients with locally confined convention al renal cell carcinomas were studied. CD44 standard form (CD44H) and v6 is oform expressions were semiquantitatively evaluated on paraffin-embedded tu mor tissue by immunohistochemistry. The prognostic value of the usual clini copathological variables and CD44 expression was tested using Kaplan-Meier plots by the log rank test and Cox multiple hazard regression analysis. Results: Mo immunostaining was observed in normal renal tissue. Thirty-two of the 66 conventional renal cell carcinomas (48%) showed CD44H membranous staining of the tumor cells. Only 2 cancers displayed CD44v6 immunostaining . Among the different clinicopathological variables analyzed, tumor stage ( p = 0.001), nuclear grade (p = 0.01), size (p = 0.02), vascular (p = 0.05) and perirenal adipose tissue invasion (p = 0.005), and CD44H expression (p = 0.01) were found to be significant prognostic parameters for survival usi ng univariate analysis; Moreover, multivariate analysis indicated stage, nu clear grade and CD44 expression as independent prognostic factors both for overall and disease-free survival. Conclusion: CD44 can be considered as a useful prognostic parameter in conv entional renal cell carcinoma and may be used in evaluation of the outcome of these tumors.