J Korean Soc Coloproctol.  2010 Oct;26(5):316-323. 10.3393/jksc.2010.26.5.316.

Effects of Delay in the Snap Freezing of Colorectal Cancer Tissues on the Quality of DNA and RNA

• Hong SH
• Baek HA
• Jang KY
• Chung MJ
• Moon WS
• Kang MJ
• Lee DG
• Park HS

• KMID: 2101525
• DOI: http://doi.org/10.3393/jksc.2010.26.5.316

Abstract

PURPOSE
The success of basic molecular research using biospecimens strongly depends on the quality of the specimen. In this study, we evaluated the effects of delayed freezing time on the stability of DNA and RNA in fresh frozen tissue from patients with colorectal cancer.
METHODS
Tissues were frozen at 10, 30, 60, and 90 minutes after extirpation of colorectal cancer in 20 cases. Absorbance ratio of 260 to 280 nm (A(260)/A(280)) and agarose gel electrophoresis were evaluated. In addition, the RNA integrity number (RIN) was assayed for the analysis of the RNA integrity.
RESULTS
Regardless of delayed freezing time, all DNA and RNA samples revealed A(260)/A(280) ratios of more than 1.9, and all DNA samples showed a discrete, high-molecular-weight band on agarose gel electrophoresis. The RINs were 7.53 +/- 2.04, 6.70 +/- 1.88, 6.47 +/- 2.58, and 4.22 +/- 2.34 at 10, 30, 60, and 90 minutes, respectively. Though the concentration of RNA was not affected by delayed freezing, the RNA integrity was decreased with increasing delayed freezing time.
CONCLUSION
According to the RIN results, we recommend that the collection of colorectal cancer tissue should be done within 10 minutes for studies requiring RNA of high quality and within 30 minutes for usual RNA studies.

Keyword

Colorectal neoplasms; Tissue banks; DNA; RNA; Quality control

MeSH Terms

Colorectal Neoplasms
DNA
Electrophoresis, Agar Gel
Freezing
Humans
Quality Control
RNA
Tissue Banks
DNA
RNA