Cancer Diagnosis Program | Biorepositories and Biospecimen Research Branch

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Impact of Freeze-thaw Cycles and Storage Time on Plasma Samples Used in Mass Spectrometry Based Biomarker Discovery Projects.

Author(s): Mitchell BL, Yasui Y, Li CI, Fitzpatrick AL, Lampe PD

Publication: Cancer Inform, 2005, Vol. 1, Page 98-104

PubMed ID: 19305635 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 long-term storage of plasma specimens at -70 degrees C and freeze-thaw cycling on MALDI-TOF mass spectrometry data. Specimens were obtained from patients who were over 65 years of age.

   Summary of Findings:

   Repeated freeze-thaw cycling changed MALDI-TOF peak intensity with a wide range of values when compared to results after just one freeze-thaw cycle. However, median changes in peak intensity were only 1.7%, 2.4%, 3.5%, and 3.1% for 2, 3, 4, and 5 freeze-thaw cycles, respectively. The data suggests that peptides and proteins are generally stable with repeated freeze-thaw cycling of plasma but 1% changed by at least 67%. Consistent with protein degradation, peaks in the >10,000 mass/charge range (m/z) generally showed a reduction in intensity with freeze-thaw cycling, but peaks at 5000-10,000 m/z were increased by freeze-thaw cycling. No differences were seen in MALDI-TOF data between specimens stored at -70 degrees C for 5 and 9 years.

   Biospecimens

   • Bodily Fluid - Plasma

   Preservative Types

   • Frozen

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Protein	MALDI-TOF MS
   Peptide	MALDI-TOF MS

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage duration	5 y 9 y
   Storage	Storage temperature	-70 degrees C
   Storage	Freeze/thaw cycling	1 cycle 2 cycles 3 cycles 4 cycles 5 cycles

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