Z Gastroenterol 2008; 46 - P323
DOI: 10.1055/s-0028-1089698

Differential expression of miRNA in gastric cancer

O Tchernitsa 1, R Schäfer 1, B Györffy 1, U Neumann 2, M Ebert 3, C Röcken 1
  • 1Charité Universitätsmedizin Berlin, Institut für Pathologie, Berlin, Germany
  • 2Charité Universitätsmedizin Berlin, Berlin, Germany
  • 3Technical University of München, Munich, Germany

Aims: In this study we investigated the differential expression of microRNA (miRNA) in gastric cancer and corresponding non-neoplastic mucosa.

Methods: Samples from gastric cancer and corresponding nonneoplastic gastric mucosa were obtained from six patients with intestinal type gastric cancer (m:f=4:1). Tissue samples were collected immediately after surgery and stored at -80°C. MiRNA was purified using the mirVana™ qRT-PCR miRNA Detection Kit (Ambion). Oligonucletide miRNA specific microarrays were spotted in the Laboratory for Functional Genetics of the Charité using Invitrogen NCode™ Multi-Species miRNA Microarray Probe Set containing 857 mammalian probes. All probes were spotted with two replica on epoxy treated slides from Corning. Labeling was done using Invitrogen NCode™ miRNA labeling system. Microarray images were obtained on an Agilent G2565AA scanner at 10µm resolution. Image analysis was performed using ImaGene software (BioDiscovery, Inc., El Segundo, USA). miRNA profiles of paired normal and tumor samples were compared. Statistical evaluation was performed using the BRB-ArrayTools version 3.6.0 beta 1. Differential expression was validated by RT-PCR using QuantiMir System (SBI System Biosciences) and an independent set of 43 gastric cancer patients.

Results: Thirty-three miRNAs were identified by Significance Analysis of Microarrays (SAM) analysis as up-regulated in gastric carcinoma compared with adjacent normal tissue. Fourteen miRNAs were also confirmed by Class Comparison analysis. All fourteen up-regulated miRNA transcripts were subsequently validated by QuantiMir. SAM analysis did not identify any commonly down-regulated miRNA in tumor tissue. The differential expression of the miRNAs was confirmed in the independent set of 43 gastric cancer patients.

Conclusion: Intestinal type gastric cancer differentially express miRNAs. Future studies will have to show whether differential expression of miRNA in gastric cancer is involved in tumor development and may serve as a putative diagnostic, prognostic or therapeutic target.