title: MicroRNAs are suitable for assessment as biomarkers from formalin-fixed paraffin-embedded tissue, and miR-24 represents an appropriate reference microRNA for diffuse large B-cell lymphoma studies.
abstract: Tissue biopsy specimens in the form of formalin-fixed paraffin-embedded tissue (FFPET) represent a valuable resource for biomarker identification and validation. However, to date, they remain an underused asset due to uncertainty regarding RNA extraction and the reliability of downstream techniques, including quantitative RT-PCR. Recently, much interest has emerged in the study of microRNAs; small single-stranded RNAs with a role in transcriptional regulation, that are thought to be well preserved in FFPET. In this study, we show that microRNA expression is comparable between FFPET and matched fresh-frozen samples (miR-17-5p: p=0.01, miR-92: p=0.003), and demonstrate that no significant deterioration in expression occurs over prolonged FFPET storage (p=0.06). Furthermore, microRNA expression is equivalent dependant on RNA extraction method (p<0.001) or DNAse treatment of total RNA (p<0.001). Finally, we validate miR-24 as a suitable reference microRNA for diffuse large B-cell lymphoma (DLBCL) FFPET studies.
authors.affiliation: Academic Haematology, Northern Institute for Cancer Research, Newcastle University, Newcastle Upon Tyne, Tyne and Wear, UK. Rachel.culpin@ncl.ac.uk
authors.forename: Rachel Emily
authors.initials: RE
authors.lastname: Culpin
authors.forename: Michal
authors.initials: M
authors.lastname: Sieniawski
authors.forename: Stephen John
authors.initials: SJ
authors.lastname: Proctor
authors.forename: Geetha
authors.initials: G
authors.lastname: Menon
authors.forename: Tryfonia
authors.initials: T
authors.lastname: Mainou-Fowler
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics; D001706:Biopsy; D015331:Cohort Studies; D005404:Fixatives; D005557:Formaldehyde; D020869:Gene Expression Profiling; D005819:Genetic Markers / Q000235:genetics*; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics* / Q000473:pathology; D035683:MicroRNAs / Q000235:genetics*; D016612:Paraffin Embedding; D011933:Reagent Kits, Diagnostic; D012015:Reference Standards; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016707:Tissue Fixation / Q000379:methods*
chemical_list: D014408:Biomarkers, Tumor; D005404:Fixatives; D005819:Genetic Markers; C543845:MIRN24 microRNA, human; D035683:MicroRNAs; D011933:Reagent Kits, Diagnostic; D005557:Formaldehyde