Comparison of the DNA Preservation in Neutral-Buffered Formalin Fixed Paraffin-Embedded Tissue and in Non-Buffered Formalin Fixed Paraffin-Embedded Tissue

Abstract

Background: The preservation of optimized DNA and its extraction from formalin-fixed, paraffinembedded (FFPE) tissues are important issues. There has been some doubt over whether 10% neutral-buffered formalin is an ideal fixation solution for DNA preservation over non-buffered for malin, as conventionally recommended. In this study, the correlation between the efficiency of DNA extraction from FFPE tissues and buffered formalin was evaluated. Methods: Several tissues with same conditions except fixatives were fixed in four different formalin solution groups and were routinely processed as paraffin-embedding protocols. DNAs were extracted from four different FFPE tissues that were stored for over 3 months and over 9 months. The quantity and quality of the DNAs were assessed with a NanoDrop ND-1000 spectrophotometer, and the polymerase chain reaction (PCR) amplification and degradation were analyzed via microchip electro phoresis. KRAS mutation analysis and microsatellite instability (BAT25) PCR were performed with each sample. Results: The results showed no remarkable difference in the four groups. Conclusions: The study findings demonstrate that DNA preservation is fairly unaffected by a neutral buf fer where there is short formalin manufacture period and an adequate formalin fixation time be fore embedding in paraffin.