The role of microRNAs (miRNAs) as predictive biomarker in advanced renal cell carcinoma (mRCC) patients (pts) with “extreme response” to tyrosine kinase inhibitors (TKIs) treatment.

470Background: MiRNAs play an important role as modulators of gene expression in a multitude of biological processes, being closely linked to the regulation of development and cell differentiation. Promising results about their value as predictors of drug response have been published in lung, colorectal cancer [Molina-Pinelo] and RCC [Garcia-Donas]. This study aims to determine whether miRNAs can predict TKIs “extreme responses” in mRCC pts. Methods: RNA from formalin fixed paraffin embedded tumor and non-tumor samples from 15 pts with mRCC was extracted with mirVana miRNA isolation kit (Ambion). We defined as TKI “extreme responders” those pts that either had a long-term response (LR) (PFS˃11 months, n=7) or that were primary refractory (PR) (progression as best response, n=8). The expression of 754 miRNAs was analyzed with TaqMan Low Density Array Human MicroRNA Panel (TLDA) (ThermoFisher). QPCR was carried out in the System of Gene Expression and Genotyping Arrays module ViiA7. A qPCR ThermoFisher soft...