posing for metastatic spread and worse prognosis. Material and Methods: Fresh-frozen tu- mor tissue specimens of 29 patients with ccRCC (15/29 patients with metastatic G3 ccRCC, and 14/29 from non-metastatic G1 ccRCC). Expression profiling was per- formed and candidate genes were selected using the Human Genome U133 Plus 2.0 Array (Affymetrix Corp., Santa Clara,CA, USA). Each tumor tissue was compared to a nonneoplastic tissue sample from the same kidney. Further analysis included an ER-scoring (event ratio scoring), Gene Set Enrichment analysis (GSEA) and subse- quent hierarchical clustering of the log- ratios of the fold-changes. Results: Among the probesets in the ranking list of differentially expressed can- didates a number of disease-relevant genes were found. Most interesting are the clus- tering results comparing G1- and G3-tu- mors, showing 24 candidates upregulated and 49 candidate genes downregulated. The main focus is on the list of 24 up- regulated gene sequences in G3-tumors in comparison to G1- tumors. Out of these gene sequences the following candidates were selected (by use of the Gene Cards data bank) for a further analysis: CDCP 1, AQP 9, RARRES 1, SLC12A8, MFJ2, SAA1, IL-20, IL-2R2, PTHLH, CP, LAMB3. Conclusion: We were able to verify the presence of several previously identified tumor associated genes and additionally we identified several other genes. Exami- nation of gene expression in each renal cell cancer subsets (G1 and G3) compared to benign renal tissue revealed genes spe- cifically overexpressed in renal cell can- cer. The expression profiles in G1 RCC are very similar to G3 RCC, suggesting that the group of genes responsible for metastatic progression may be rather smal- l.In the search for candidates genes se- lected from raw data the main problem is the lack of a standard workflow. Until to- day there is no defined biostatistic method or procedure as standard to com- pare different studies and to reduce the divergence of results. UP-01.147 Accuracy of Conventional Pathologic Predictive Factors in Histological Subtype Chromophobe Renal Cell Carcinoma Rodríguez Faba O, Pardo P, Breda A, Palou J, Algaba F, Ochoa C, Rosales A, Villavicencio H Fundació Puigvert, Barcelona, Spain Introduction and Objective: Chromo- phobe renal cell carcinoma (RCC) is sug- gested as a biological tumor of low malig- nant potential with 5-year and 10-year survival rates of 78% to 100% and 80% to 90%, respectively. The conventional prog- nostic parameters of progression are still under debate. Moreover the usefulness of Fuhrman grade has been questioned by theUICC Workgroup on the grading of RCC. Our objective is to evaluate the prognostic effectiveness of conventional pathologic predictive factors in a single center experience series of Chromophobe RCC. Materials and Methods: We retrospec- tively reviewed the data of 73 patients with Chromophobe RCC treated with rad- ical nephrectomy between 1992-2010. Forty six (63%) men with mean age of 72 years (28-81). Clinicopathologic features analyzed were TNM stage, Fuhrman grade, microvascular invasion, tumoral necrosis, tumoral thrombus, positive surgical mar- gins (PSMs), perinephritic fat invasion and collecting system involvement, and were correlated with outcome (recurrence) in univariate and multivariate analysis by us- ing a Cox proportional hazards regression model. Results: Eight (11%) patients recurred at a median time of 31.7 months (5.37- 124.33) with a median follow-up of 60.2 months (0.37-160.2). In univariate analy- sis, the following variables were signifi- cantly associated with recurrence: Stage (p0.0001), Fuhrman grade III or IV (p0.031), microvascular invasion (p0.0001) and PSMs (p0.0001). In mul- tivariate analysis only stage remained as independent predictive factor for recur- rence in pT1 vs pT2 (p0.02; OR 0.27 95%CI 0.03-0.258) and pT2 vs higher stage (p0.037; OR 0.173 95%CI 0.033- 0.896). The main limitations of this study are its retrospective nature and a low number of cases. Conclusions: The pT stage of tumour predicts an aggressive phenotype in cromophobe RCC. The effectiveness of Fuhrman nuclear grading is not useful in this subtype of RCC. UP-01.148 E2EPF as an Ubiquitin Carrier Protein Plays a Role in the Cancer Genesis of Papillary Renal Cell Carcinoma Roos F 1 , Evans A 2 , Brenner W 1 , Thomas C 1 , Furge K 3 , Hampel C 1 , Thüroff J 1 , Ohh M 4 1 Dept. of Urology, Medical Center, Johannes Gutenberg University, Mainz, Germany; 2 Dept. of Pathology, University Health Network, Princess Margaret Hospital, Toronto, Canada; 3 Dept. of Cancer Genetics, Van Andel Research Institute, Grand Rapids, USA; 4 Dept. of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada Introduction and Objectives: Molecular pathways associated with pathogenesis of sporadic papillary renal cell carcinoma (PRCC), the second most common form of kidney cancer, are poorly understood. There is no effective therapy for meta- static PRCC, and patients are often ex- cluded from clinical cancer trials. Material and Methods: We analyzed primary tumour specimens from 35 PRCC patients treated by nephrectomy via gene expression analysis and tissue microarrays (TMAs) constructed from additional 57 paraffin-embedded PRCC samples via im- munohistochemistry. Gene products were validated and further studied by Western blot analyses using primary PRCC tumour samples and established RCC cell lines, and potential associations with pathologi- cal variables and survival in 27 patients with follow-up information were deter- mined. Results: The expression of E2-EPF ubiqui- tin carrier protein, which targets the prin- cipal negative regulator of hypoxia-induc- ible factor (HIF), von Hippel-Lindau (VHL) protein, for proteasome-dependent degra- dation, is markedly elevated in the major- ity of PRCC tumors exhibiting increased HIF1 expression and associated with poor prognosis. In addition, we identified multiple hypoxia-responsive elements (HREs) within the E2-EPF promoter and demonstrate for the first time that E2-EPF is a hypoxia inducible gene directly regu- lated via HIF1. Conclusions: The present findings impli- cate deregulation of the oxygen-sensing pathway in PRCC, and provide a compel- ling argument that a select group of PRCC patients exhibiting strong tumor-specific E2-EPF or hypoxic profile may represent responders to small molecule inhibitors designed to antagonize the HIF-signaling pathway. HIF-responsive gene. It is up- regulated in the majority of pRCC. UP-01.149 Immunophenotype, Differentiation Capacity and Tumor Promoting Potential of Renal Cell Carcinoma- Derived Mesenchymal Stem Cell-Like Stromal Cells Börger V 1 , Rottke D 5 , Sorg U 2 , Hatina J 3,6 , Heikaus S 4 , Opalka B 7 , Ackermann R 3 , Wernet P 1 , Sorg R 1 1 University Hospital Düsseldorf, Inst. for UNMODERATED POSTER SESSIONS UROLOGY 78 (Supplement 3A), September 2011 S235