Influence of Cold Ischemia Time and Storage Period on DNA Quality and Biomarker Research in Biobanked Colorectal Cancer Tissues / 고신대학교의과대학학술지

ABSTRACT

Objectives@#Biobanking plays an important role in future research. Assessment and control of the preanalytical variables of biobanked tissues are fundamentals for the optimal use of biospecimens. @*Methods@#Forty-five colorectal cancer (CRC) tissues stored at -80℃in Bio-Resource Bank were evaluated to define the influence of cold ischemia time (CIT) and storage period (SP) on DNA quality in biobanked tissues. Three CITs (less than 30 minutes (CIT-1), 30-45 minutes (CIT-2), and 45-60 minutes (CIT-3)) and three SPs (less than 1 year (SP-1), 2-3 years (SP-2), and 4-5 years (SP-3)) were chosen. NanoDrop spectrophotometer was used to determine the 260/280 ratio for DNA purity. DNA integrity was analyzed by a UV transilluminator following electrophoresis on 2% agarose gel. To evaluate the practical usability of DNA for biomarker research, KRAS mutation status was assessed by PCR amplification. @*Results@#All DNA specimens had a 260/280 ratio ranging between 1.8 and 2.0 with the exception of one specimen (CIT- 2/SP-2 group). For DNA integrity, DNA appeared as a compact, high-molecular-weight band with no or scanty low-molecular- weight smears. The concordance of KRAS mutation status between paired biobanked frozen tissues and formalin-fixed paraffin-embedded tissues was 100%. DNA remained stable in CRC tissues kept at room temperature for up to 1 hour and long-term storage up to 5 years. @*Conclusions@#Storage conditions of our biobank are suitable for long-term (at least five years) specimen preservation with high DNA quality. These results have practical implications that could affect banking guidelines.