microarrayAims: MRP-1, LRP and TOPO-II are all associated with protection of the cells from the adverse eff ects of variouschemotherapeutics. The aim of this study was to measure the expression of these proteins in Wilms' tumor (WT).Materials and Methods: TMA block was constructed from 14 samples of WT's and from xenografts derived fromthem. Sections of the TMA were used for immunostaining against MRP-1, LRP and TOPO-IIa.Results: All normal kidneys expressed MRP-1 but were either weakly or negatively stained for LRP and TOPO-IIa.In WT samples, MRP-1 was universally expressed, exclusively in the tubular component, while there was no expressionof LRP and TOPO-IIa showed heterogeneous distribution. The xenografts varied in their MRP-1 and TOPO-IIaexpression and exhibited weak/negative staining of LRP.Conclusions: This study shows that although all the proteins evaluated, had diff erent expression patterns in thetumor samples, the most prominent changes in expression were found for MRP-1. The exact clinical implications ofthese changes in expression and their relevance to the resistance of these tumors to chemotherapy requires furtherinvestigation. The fi nding of diff erent expression profi les for the multidrug resistance proteins in the original WT'sand their xenografts suggests that the results of animal cancer models may be diffi cult to interpret.

Departments of Pathology and Urology Chaim Sheba Medical Center Tel Aviv University Tel Aviv

References provided by Crossref.org

Lit.: 21