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Detection of Post-translational Modifications on Native Intact Nucleosomes by ELISA
Published on: April 26, 2011
Long-term stability of circulating nucleosomes in serum
Stefan Holdenrieder1, Joachim Von Pawel, Dorothea Nagel
1Institute of Clinical Chemistry, University Hospital Munich-Grosshadern, Munich, Germany. Stefan.Holdenrieder@med.uni-muenchen.de
Anticancer Research
|July 2, 2010
Summary
Circulating nucleosomes are valuable for cancer monitoring. However, their levels decrease significantly over long-term storage at -70°C, impacting retrospective studies.
Area of Science:
- Biochemistry
- Oncology
- Clinical Diagnostics
Background:
- Circulating nucleosomes (DNA-histone complexes) show promise as diagnostic and prognostic markers in various diseases, including cancer.
- Retrospective analysis of stored serum samples is common, necessitating an understanding of nucleosome stability during long-term storage.
Purpose of the Study:
- To evaluate the stability of circulating nucleosomes in serum samples stored long-term at -70°C.
- To determine the impact of storage duration on nucleosome levels for retrospective diagnostic applications.
Main Methods:
- 154 serum samples from cancer patients, stored at -70°C, were analyzed for nucleosome levels using ELISA.
- Samples were measured twice: initially 6-9 months post-collection and again after a median interval of 64.8 months.
Main Results:
- Nucleosome levels significantly decreased by a median of 32.0% (p<0.0001) between the first and second measurements.
- Despite the decrease, nucleosome concentrations showed a strong correlation (R=0.92; p<0.0001) between measurements.
- Individual patient data revealed parallel trends in nucleosome signal changes, with 89% concordance in increases and decreases.
Conclusions:
- Retrospective studies using serum nucleosomes are feasible if samples are collected within homogeneous time intervals and preanalytical conditions are strictly followed.
- The observed decrease in nucleosome levels highlights the importance of standardized protocols for reliable long-term storage and analysis.
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