Feasibility of plasma circulating free RNA (cfRNA) microarray profiling and gene-specific prognostic associations in metastatic urothelial carcinoma (mUC) patients receiving platinum-based chemotherapy.

333 Background: The current study was undertaken to determine the feasibility of detection and expression profiling of cfRNA in mUC patients treated with platinum-based chemotherapy. Methods: Plasma samples were identified from consented mUC subjects treated with platinum-based therapy at the IU Simon Cancer Center (IUSCC) from 12/2008 – 8/5/2010. The primary feasibility measure was the detection of cfRNA at any quantitative level. An IUSCC urologic cancer 48-gene array was designed. After cfRNA extraction and cDNA preparation, cDNA were amplified in a specific target amplification step using gene-specific primers for the 48 genes in the array. Gene expression analysis was performed on amplified cDNA using 96.96 format DELTAgene microfluidic Dynamic Array platform (Fluidigm). CT values were calculated for each gene after normalization against expression of internal control gene, GAPDH. To identify associations between individual gene expression and OS, a Cox proportional hazards regression analysis was pe...