Utilizing mRNA extracted from small, archival formalin-fixed paraffin-embedded prostate samples for translational research: assessment of the effect of increasing sample age and storage temperature.
Author(s): Stewart GD, Baird J, Rae F, Nanda J, Riddick AC, Harrison DJ
Publication: Int Urol Nephrol, 2011, Vol. 43, Page 961-7
PubMed ID: 21448682 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to determine the effects of preservation method, storage duration, and storage temperature of benign prostate tissue on RNA quantity and quality.
Conclusion of Paper
Snap-frozen tissue yielded a greater quantity and quality of mRNA than formalin-fixed paraffin-embedded (FFPE) tissue. However, all snap-frozen and FFPE specimens yielded mRNA of sufficient quantity and quality for subsequent analysis even after storage for 112 days, regardless of storage temperature. Significantly higher cycle threshold (Ct) values were found in 15 year old FFPE resections and biopsies than in 2-5 year old specimens. Nevertheless, with the exception of one archived block containing 2 biopsies, all archived FFPE specimens yielded mRNA of sufficient quantity/quality for further analysis.
Studies
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Study Purpose
The purpose of this study was to determine the effects of preservation method, storage duration, and storage temperature of benign prostate tissue on RNA quantity and quality. 3 resection specimens were divided and snap frozen or FFPE. Snap-frozen specimens were stored at -80°C while FFPE blocks were stored at either room temperature or 4°C. RNA was extracted after designated storage and beta-actin real time qRT-PCR was performed using 4 different primers. An additional 36 FFPE resection specimens and 10 biopsies that were archived for 2-15 y were also examined.
Summary of Findings:
Snap-frozen tissue yielded a greater quantity and quality of mRNA than FFPE tissue, as evaluated by beta-actin real time qRT-PCR (p≤0.03). However, all snap-frozen and FFPE specimens (stored at 4°C or room temperature) yielded mRNA of sufficient quantity and quality for subsequent analysis (Ct<30) even after storage for 112 days. Significantly higher Ct values were found in 15 year old FFPE resections and biopsies than in 2-5 year old resections or 5 year old biopsies, respectively (P=0.0031 and P=0.0038, respectively). Nevertheless, with the exception of one archived block containing 2 biopsies (Ct=44), all archived FFPE specimens yielded mRNA of sufficient quantity/quality for further analysis (Ct<30).
Biospecimens
Preservative Types
- Frozen
- Formalin
Diagnoses:
- Neoplastic - Benign
Platform:
Analyte Technology Platform RNA Real-time qRT-PCR Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Storage duration 0 d
7 d
14 d
28 d
56 d
112 d
2 y
5 y
10 y
13 y
15 y
Biospecimen Acquisition Method of tissue acquisition Surgical resection
Biopsy
Storage Storage temperature -80°C
4°C
Room temperature
Biospecimen Preservation Type of fixation/preservation Snap frozen
Formalin (buffered)