1409 POSTER Highly Sensitive Detection of MicroRNa and MRNa From FFPE Tissue and Blood Samples by Expression Microarray

Abstract

Background: Gene expression profiling of readily available clinical samples, such as blood or FFPE tissue, is a promising method to discover novel diagnostic markers. As RNA is subjected to degradation even in properly-collected tissue samples, it is more difficult to obtain intact RNA from FFPE or body fluid samples for diagnostic analysis. 3D-Gene is highly sensitive gene expression microarray, featuring the unique microcolumnar structure on the platform substrate and the beads agitation system during the hybridization reaction. Using 3D-Gene, we achieved highly sensitive and reproducible detection of mRNA or miRNA from FFPE tissue samples. Material and Methods: Total RNA was extracted from human serum, plasma and frozen or FFPE tissue samples, with the recommended protocol for each sample. For mRNA detection, total RNA was reversetranscribed to cDNA and labeled with fluorescent dye directly or after the amplification. For miRNA detection, total RNA was labeled with fluorescent dye directly. These pretreated target nucleotides were hybridized to 3DGene while the hybridized buffer containing target nucleotides was agitated by beads during hybridization. The hybridized microarrays were washed and scanned for image acquisition. Results: The result was highly correlated with the expression profiles from frozen tissue samples. Furthermore, exosomal miRNA from serum or plasma was also detected with high sensitivity and reproducibility. From these analyses of FFPE tissue or blood samples, we found potential miRNA biomarkers for various cancers. i. Using 3D-Gene, we detected mRNA expression profile from FFPE samples with high reproducibility. We also showed high correlation of the expression profiles between FFPE and frozen tissue samples. Furthermore, microRNA obtained from frozen as well as FFPE tissue samples was reproducibly detected at atto-molar level. Some miRNA biomarkers for various cancers were found from FFPE samples. ii. Serum and plasma are suggested to contain microsomes in which miRNA is enclosed. miRNA from serum and plasma samples were detected with high sensitivity and reproducibility with 3D-Gene. Some miRNA biomarkers for various cancers were found from patients’ serum. Conclusions: The Application of our 3D-Gene for the gene expression analysis of clinical samples could bring a formally unexplored venue in the biomarker discovery and diagnostic field.