Impact of serum storage conditions on microRNA stability.

Author(s): Grasedieck S, Schöler N, Bommer M, Niess JH, Tumani H, Rouhi A, Bloehdorn J, Liebisch P, Mertens D, Döhner H, Buske C, Langer C, Kuchenbauer F

Publication: Leukemia, 2012, Vol. 26, Page 2414-6

PubMed ID: 22504138 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of short-term storage (10 days) at room temperature, -20 degrees C, or -80 degrees C with or without freeze-thaw cycling, 20 months of storage at -20 degrees C or -80 degrees C, and long-term storage (0-10 years) at -20 degrees C on levels of miRNA in serum. For the study on the effects of storage for 10 days, with or without freeze-thaw cycling, RNA was extracted from the serum of three healthy individuals. For the study on the effects of storage for 20 months, RNA was extracted from the serum of three patients with multiple myeloma (MM). For the study on long term serum storage at -20 degrees C, specimens were obtained from the same 3 MM patients in 2002, 2004, 2006, 2008 and 2010. RNA extractions were performed using miRNeasy.

   Summary of Findings:

   There were no differences in the average CT values and small RNA yield between specimens stored for 10 days or 20 months at -20 or -80 degrees C. However, the average CT value for miR-93 was lower for specimens stored for 20 months at -20 degrees C than -80 degrees C (p=0.04), and miRNA PCR panels revealed that 17.1% and 8.2% of miRNAs were 1 CT higher and lower, respectively in specimens stored at -20 degrees C than those stored at -80 degrees C. Specimens subjected to 10 freeze-thaw cycles over the course of 10 days had significantly higher CT values (p<0.01) and significantly lower yield of small RNAs (p<0.01) compared to those subjected to just 1 freeze-thaw cycle (frozen at -80 degrees C). Still, specimens stored at room temperature for 10 days had even lower small RNA yields (p=0.05) and higher CT values (p=0.017) than those subjected to 10 freeze-thaw cycles (frozen at -80 degrees C). Significantly higher CT values were observed for serum specimens stored at -20 degrees C for 4 years or more than for those stored for less than 4 years (p<0.01), but there was no difference between levels in specimens stored for 2 years at -20 degrees C and recent specimens.

   Biospecimens

   • Bodily Fluid - Serum

   Preservative Types

   • Frozen

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   RNA	Real-time qRT-PCR
   RNA	Automated electrophoresis/Bioanalyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage duration	10 days 20 months 0 years 2 years 4 years 6 years 8 years 10 years
   Storage	Storage temperature	Room temperature -20 degrees C -80 degrees C
   Storage	Freeze/thaw cycling	1 cycle 10 cycles
   Real-time qRT-PCR Specific	Targeted nucleic acid	miR-223 miR-451 miR-93 miR-24

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