title: High stability of microRNAs in tissue samples of compromised quality.
abstract: Degradation of tissue samples limits performing RNA-based molecular studies, but little is known about the potential usefulness of samples of compromised quality for studies focused on miRNAs. In this work we analyze a series of cryopreserved tissue samples (n = 14), frozen samples that underwent a severe thawing process (n = 10), and their paired formalin-fixed paraffin-embedded (FFPE) tissue samples (n = 24) from patients with breast cancer obtained during primary surgical resection and collected in 2011. Quality and integrity analyses of the total and small fraction of RNA were carried out. Recovery of specific RNA molecules (miRNAs hsa-miR-21, hsa-miR-125b, and hsa-miR-191; snoRNA RNU6B; and mRNAs GAPDH and HPRT1) was also analyzed by quantitative RT-PCR. Our results suggest that visualisation of the small RNA electrophoretic profiles obtained using the Agilent 2100 bioanalyzer makes it possible to differentiate between the three groups of samples (optimally frozen, thawed, and FFPE). We demonstrate that specific miRNA molecules can be similarly recovered from different tissue sample sources, which supports their high degree of stability. We conclude that miRNAs are robustly detected irrespective of the quality of the tissue sample. In this regard, a word of caution should be raised before degraded samples are discarded: although prior quality assessment of the biological material to be analyzed is recommended, our work demonstrates that degraded tissue samples are also suitable for miRNA studies.
authors.affiliation: Biobank, INCLIVA Biomedical Research Institute, Avenida Blasco Ibáñez, 17, 46010, Valencia, Spain.
authors.forename: Lorena
authors.initials: L
authors.lastname: Peiró-Chova
authors.forename: María
authors.initials: M
authors.lastname: Peña-Chilet
authors.forename: José Antonio
authors.initials: JA
authors.lastname: López-Guerrero
authors.forename: José Luis
authors.initials: JL
authors.lastname: García-Giménez
authors.forename: Elisa
authors.initials: E
authors.lastname: Alonso-Yuste
authors.forename: Octavio
authors.initials: O
authors.lastname: Burgues
authors.forename: Ana
authors.initials: A
authors.lastname: Lluch
authors.forename: Jaime
authors.initials: J
authors.lastname: Ferrer-Lozano
authors.forename: Gloria
authors.initials: G
authors.lastname: Ribas
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics*; D015925:Cryopreservation; D005260:Female; D006801:Humans; D016612:Paraffin Embedding; D020871:RNA Stability; D012333:RNA, Messenger / Q000032:analysis*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016707:Tissue Fixation / Q000379:methods
chemical_list: D012333:RNA, Messenger