title: Preservation of RNA for functional analysis of separated alleles in yeast: comparison of snap-frozen and RNALater solid tissue storage methods.
abstract: BACKGROUND
  The aim of the present study was to compare RNALater with the usual method of liquid nitrogen snap freezing as a surrogate mRNA preservation method for functional analysis of separated alleles in yeast (FASAY).
  
  
  METHODS
  A total of 81 patients with transitional cell carcinoma of the bladder underwent fresh tissue biopsies directly transferred into RNALater and stored at room temperature or at 4 degrees C for increasing time intervals until RNA processing. From this cohort of patients, 53 paired snap-frozen and RNALater preservative-suspended tissues were obtained. Samples immediately frozen in liquid nitrogen were further stored at -80 degrees C.
  
  
  RESULTS
  Of the 81 RNALater samples, 14 were not processed for FASAY because of RNA degradation. Of the remaining 67 samples, 15 (22%) were FASAY-positive. Identical FASAY results were found for 50 of 53 (94.4%) paired samples and the percentage of red yeast colonies was highly correlated (Cohen's kappa<0.82; p<0.00001). A single p53 missense mutation was found in each of the three discordant positive FASAY and was identical in each concordant positive sample (10/53). Storing samples in RNALater at room temperature for 3 days and at 4 degrees C for less than 1 month provided high-quality mRNA suitable for FASAY.
  
  
  CONCLUSIONS
  Our results demonstrate that RNALater is a suitable and flexible alternative to snap freezing for FASAY analysis.
authors.affiliation: Centre for Applied Molecular Technology, Université catholique de Louvain, Brussels, Belgium.
authors.forename: Anne-France
authors.initials: AF
authors.lastname: Dekairelle
authors.forename: Sébastien
authors.initials: S
authors.lastname: Van der Vorst
authors.forename: Bertrand
authors.initials: B
authors.lastname: Tombal
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Gala
mesh_terms: D000483:Alleles; D002295:Carcinoma, Transitional Cell / Q000473:pathology; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000737:chemistry; D020869:Gene Expression Profiling / Q000379:methods*; D006801:Humans; D009584:Nitrogen / Q000737:chemistry; D012313:RNA / Q000235:genetics*; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D014021:Tissue Preservation / Q000379:methods*; D001749:Urinary Bladder Neoplasms / Q000473:pathology; D015003:Yeasts
chemical_list: D003451:Cryoprotective Agents; D012333:RNA, Messenger; D012313:RNA; D009584:Nitrogen