Detection of microRNAs in archival cytology urine smears

PLoS One. 2013;8(2):e57490. doi: 10.1371/journal.pone.0057490. Epub 2013 Feb 28.

Abstract

MicroRNAs' dysregulation and profiling have been demonstrated to be clinically relevant in urothelial carcinoma (UC). Urine cytology is commonly used as the mainstay non-invasive test for secondary prevention and follow-up of UC patients. Ancillary tools are needed to support cytopathologists in the diagnosis of low-grade UC. The feasibility and reliability of microRNAs profiling by qRT-PCR analysis (miR-145 and miR-205) in archival routine urine cytology smears (affected by fixation/staining [Papanicolau] and room temperature storage) was tested in a series of 15 non-neoplastic and 10 UC urine specimens. Only samples with >5,000 urothelial cells and with <50% of inflammatory cells/red blood cells clusters were considered. Overall, a satisfactory amount of total RNA was obtained from all the considered samples (mean 1.27±1.43 µg, range 0.06-4.60 µg). Twenty nanograms of total RNA have been calculated to be the minimal total RNA concentration for reliable and reproducible miRNAs expression profiling analysis of archival cytological smears (slope= -3.4084; R-squared=0.99; efficiency=1.94). miR-145 and miR-205 were significantly downregulated in UC samples in comparison to non-tumor controls. These findings demonstrate that urine archival cytology smears are suitable for obtaining high-quality RNA to be used in microRNAs expression profiling. Further studies should investigate if miRNAs profiling can be successfully translated into clinical practice as diagnostic or prognostic markers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Feasibility Studies
  • Humans
  • MicroRNAs / urine*
  • Reverse Transcriptase Polymerase Chain Reaction / methods

Substances

  • MicroRNAs

Grants and funding

This work was supported by a grant from the Veneto Region (Ricerca Finalizzata 2006), by a grant from the University of Padova (Progetti di Ricerca di Ateneo 2011) and by the Cariparo Foundation Excellence-grant 2011/2012. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.