Biomolecular characterization of formalin-fixed paraffin-embedded primary renal tumor specimens.
421 Background: Renal cell carcinoma (RCC) is the most common type of kidney cancer. It is required a better understanding of signalling pathways involved in renal cells. Methods: We assessed using immunohistochemistry (IHC) and quantitative real-time PCR (qPCR) with SYBR Green the profile of predictive markers involved in the cascade of events leading to the formation and progression: invasiveness, angiogenesis and antiapoptotic mechanisms. 80 RCC tissues were detected by IHC. RNA of quality only was obtained in 72 (80% clear RCC, 10% papillary RCC and 10% chromophobe RCC) to carry out the study of gene expression through qPCR. A pool of normal kidney-derived RNA samples (N=5) was used as healthy control. GAPDH and YWHAZ were used as reference genes. GenEx software was used for qPCR data processing and analysis. Nonparametric tests (Pearson’s correlation coefficient test and Spearman’s rho test, Kruskal — Wallis and Mann — Whitney) were applied for statistical data analysis (SPSS 19). Results: p53 showed higher expression in those cases with Furhman grade I (p=0.036). Moreover p53 showed a positive association with VEGF, GLUT1, GLUT4, VEGFR-2 and VHL (r=0.241, sig. level 0.05; r=0.291, sig. level 0.01; r=0.456, sig. level 0.01; r=0.187, sig. level 0.097 and Spearman’s rho=0.269, sig. level 0.05 respectively). Hif1- α, Hif1- β, Notch1 and Notch3 were upregulated in chromophobe RCC (p=0.045, p=0.03, p=0.03 and p=0.02 respectively). Hif1- α and Notch3 were upregulated in clear RCC (p=0.034 and p=0.041 respectively). Spearman’s correlation coefficient showed a strong positive correlation between Nocth1-4 members and their receptors and Hif1-α and β genes. Highlight the correlation found between: Notch1 and Hif1-α (Spearman’s rho = 0.740, significance level 0.01) and Hif1-β and Jagged1 (Spearman’s rho = 0.752, significance level 0.01). Conclusions: The pathway involving the tumor suppressor gene p53 could regulate tumor angiogenesis. Co-expression of Notch receptors, their ligands and Hif-1 α and Hif1- β subunits may play a role in human RCC. Notch cascade may represent a novel and therapeutically accessible pathway in chromophobe and clear RCC. More detailed studies of these crossing pathways are in progress.