Evaluating the gene expression of frozen tissue-derived prognostic signatures in FFPE colorectal cancer samples. Homo sapiens

Defining molecular features that can predict the recurrence of colorectal cancer (CRC) for stage II-III patients remains challenging in cancer research. Most available clinical samples are Formalin-Fixed and Paraffin-Embedded (FFPE). NanoString nCounter® and Affymetrix GeneChip® Human Transcriptome Array 2.0 (HTA) are the two platforms marketed for high-throughput gene expression profiling for FFPE tissue samples. In this study, to identify an optimal platform for the gene expression profiling of FFPE CRC samples, we evaluated the expression of 516 genes from published frozen tissue-derived prognostic signatures in 42 CRC patient samples measured by these two platforms. Based on HTA platform-derived data, we identified both gene (99 individual genes, FDR < 0.05) and gene set (four of the six reported multi-gene signatures with sufficient information for evaluation, P < 0.05) expression differences associated with survival outcomes. Using nCounter platform-derived data, only one of the six multi-gene signatures (P < 0.05) but no individual gene was associated with survival outcomes. Therefore, the HTA appears to provide a more robust gene expression dataset using genes from published gene signatures. Our study indicated that sufficiently high quality RNA could be obtained from FFPE tumor tissues to detect frozen tissue-derived prognostic gene expression signatures for CRC patients. Overall design: In this study, we evaluated the expression of 516 genes from published frozen tissue-derived prognostic signatures in 42 Stage II & III CRC patients samples measured by NanoString nCounter and Affymetrix GeneChip Human Transcriptome Array 2.0 platforms. ***This represents the NanoString component only.***