Objective: Clear cell renal cell carcinoma (ccRCC) generally presents with a micronodular phenotype (MP) due to high expression levels of vascular endothelial growth factor (VEGF-A). Earlier we have shown that MP is associated with shedding of multicellular tumor fragments (MTF) into the circulation and pulmonary metastasis. We hypothesized that VEGF inhibition will destroy MP resulting in less MTF. Method: 8 ccRCC patients were treated for 4 weeks by daily administration of Sorafenib (400 mg bid). Three days after therapy, nephrectomy was performed and kidneys were perfused via the arteria renalis. Venous perfundate was filtered and processed to AgarCytoblocks for MTF. Treatment effects were studied using immunohistochemistry. Results: All tumors were ccRCC as demonstrated by high VEGF-A expression. None of the tumors showed MP after Sorafenib treatment. Tumors showed large areas of necrosis and fibrinoid necrosis of the blood vessels, concomitant with profound perivascular inflammation. 6/8 ccRCC patients (75 %) had MFT vs 33 % in a control group (p= 0.03 Fisher's exact test). Individual tumor cells in the MTFs showed increased mitotic activity. Conclusion: Sorafenib destroys MP in ccRCC, attacks tumor vasculature, causes extensive necrosis and inflammation. Post-treatment MTF are increased in venous perfundate. Care should therefore be taken with neo-adjuvant sorafenib treatment of ccRCC. Objective: Claudins are major transmembrane proteins of tight junctions. As the disruption of their function have important impact on tumorogenesis, invasion and metastasis. Claudins became a focus of interest for targeting therapies. Although their expression profiles have been studied in many organs, researches on Claudin expression in bladder are in limited number. The aim of this study is to present the differential expression of Claudins in invasive urothelial cell carcinoma (IUCC), noninvasive papillary urothelial carcinoma (NPUC), carcinoma in-situ (CIS), papillary urothelial neoplasm of low malignant potentiall (PUNLMP) and control group (CG). Results: 83 cases (31 IUCC -further divided into:15 muscle invasive UCC, 16 UCC with lamina propria invasion-, 17 NPUC, 13 PUNLMP, 7 CIS and 15 CG) were evaluated with Claudin-1, 3, 4. Interestingly, high Claudin-1 and -3 score in CG (100 %, 80 %), decreased significantly in all non-invasive lesions (mean 18 %, 22 %). Claudin-4 expression appeared to decrease in IUCC vs. Others (%52 vs mean %82). Conclusion: Higher expression of Claudin-4 in low-grade and non-invasive lesions may be used as a diagnostic tool. In terms of Claudin-1 and -3, their decreased expression in non-invasive lesions when compared to CG and their trend to show more increased expression in IUCC needs to be studied further in larger studies.