Tissues from routine pathology archives are suitable for microRNA analyses by quantitative PCR
OPEN ACCESS- 1Institute of Pathology, University Hospital of Cologne, Cologne, Germany
- 2Center for Molecular Medicine, University of Cologne, Cologne, Germany
- Margarete Odenthal, Institute of Pathology, University Hospital Cologne, Kerpener Straße 62, 50924 Cologne, Germany; m.odenthal{at}uni-koeln.de
- Accepted 12 August 2008
- Published Online First 28 August 2008
Abstract
Background: MicroRNAs have recently taken centre stage as short non-coding RNAs that regulate mRNA expression.
Aim/Methods: To assess the feasibility of using microRNA techniques on routinely processed tissues, the accessibility of two representative microRNAs was examined by real-time quantitative PCR in 86 human formalin-fixed paraffin-embedded (FFPE) samples from liver, breast, bone marrow, lymphatic tissues and colon. Murine liver was used to analyse the influence of fixation time and different fixatives.
Results: High-quality microRNA was successfully extracted from routinely processed formalin-fixed tissues, resembling PCR amplification results from snap-frozen material analysed in parallel. While fixation time did not affect microRNA accessibility, non-buffered formalin or fixative supplements such as glutaraldehyde influenced PCR results. Storage of human tissues for up to 7 years did not cause a significant deterioration of microRNA. However, microRNA quality in human archival material following routine processing 10–20 years ago was decreased. Oxidation by ambient air during storage and fixation in non-buffered formalin is a possible reason for loss of microRNA quality.
Conclusion: The assessment of microRNAs in readily obtained formalin-fixed paraffin-embedded samples is a highly promising tool in molecular pathology when similarly treated samples are analysed. Therefore, microRNA analyses will gain wider acceptance as an adjunct to morphological tissue assessment in routine pathology and retrospective studies.
Footnotes
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US and HV contributed equally to this work.
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Funding: This work was partly supported by the Koeln Fortune Program/Faculty of Medicine, University of Cologne (to HV), and by the program for Research and Education of the Medical Faculty of the University Cologne.
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Competing interests: None.
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Ethics approval: Ethics approval was obtained.
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