Description
The prognosis of colorectal cancer (CRC) stage II and III patients is still a challenge due to the difficulties of finding robust biomarkers and assays. The majority of published gene signatures of CRC have been generated on frozen colorectal tissues. Because collection of fresh frozen tissues is not routine and the quantity and quality of RNA derived from formalin-fixed paraffin-embedded (FFPE) tissues is vastly inferior to that derived from fresh frozen tissue, a clinical test for improving staging of colon cancer will need to be designed for FFPE tissues in order to be widely applicable. We have designed a custom Nanostring nCounter assay for quantitative assessment of expression of 414 gene elements consisting of multiple published gene signatures for colon cancer prognosis, and systematically compared the gene expression quantification between nCounter data from FFPE and Affymetrix microarray array data from matched frozen tissues using 414 genes.