Abstract 4127: Expression profiling of paired formalin-fixed, paraffin-embedded (FFPE) and fresh-frozen tissue samples on Ion Torrent PGMTM.

Abstract

Abstract Archived formalin-fixed paraffin-embedded (FFPE) specimens represent excellent resources for biomarker discovery, but it has been a major challenge to study gene expression in these samples due to mRNA degradation and modification during fixation and processing. We have developed methods for small RNA and whole transcriptome analysis of FFPE samples on the Ion Torrent PGM™ System using Ion total RNA-Seq Kit v2 and RiboMinus Eukaryote System v2. Paired FFPE and fresh-frozen RNA samples from lung adenocarcinoma tissue were used in this study. Small RNA libraries were prepared using the Ion Total RNA-Seq kit v2 with modified protocol, followed by sequencing on PGM™ system. Results show that small RNA extracted from FFPE sample was successfully converted to small RNA library. Although percentage of reads mapped to miRBase was slightly lower when compared to fresh-frozen sample, the overall miRBase coverage and detection sensitivity were comparable. For whole transcriptome analysis, RiboMinus Eukaryote System v2 kit was used to deplete rRNA from FFPE samples, followed by library construction using the Ion Total RNA-Seq kit v2 with a modified protocol. Significant reduction in rRNA reads was observed after sequencing. High RefSeq correlations were observed between fresh-frozen and FFPE samples. In conclusion, a full spectrum of gene expression data, from both small RNA and whole transcriptome, were generated from FFPE samples using Ion Total RNA-Seq kit v2 with modified protocols. High correlations were observed between paired fresh-frozen and FFPE samples, demonstrating the reliability of the modified workflow for gene expression profiling on FFPE samples. This study provides feasibility for systematic gene expression analysis on FFPE samples from cancer and other diseases. Citation Format: Jian Gu. Expression profiling of paired formalin-fixed, paraffin-embedded (FFPE) and fresh-frozen tissue samples on Ion Torrent PGMTM. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4127. doi:10.1158/1538-7445.AM2013-4127