RNA Preservation in FFPE Tissues Requires Pre-Analytical Standardized Processing.
Gianni Bussolati. University of Turin, Italy
Background: Preservation of RNA for Gene Expression profiling is notoriously poor in Formalin Fixed Paraffin Embedded (FFPE) tissues, thus hampering extended gene sequencing in routinely processed histo-pathological tissues.
Design: Our hypothesis was that RNA degradation in surgical biopsies is caused by RNAse activation before and during formalin fixation and that low temperature (4°C) could inhibit this activity and prevent degradation. In our Hospital (a large, pavillon hospital in Piedmont, Italy) the traditional habit of transferring specimens from the surgical theatre to the Pathology laboratory while immersed in large boxes filled with formalin was substituted by Under-Vacuum sealing (UVS) using the TissueSAFETM apparatus. Specimens, routinely U.V. sealed immediately after surgical removal, were kept at 4°C for 1-72 h. until transfer. Grossing, fixation in Phosphate-buffered Formalin (PBF) and paraffin embedding followed. Selected specimens were processed by a 24 h. fixation in PBF at controlled temperature.
Results: UVS was well accepted by both Surgery and Pathology staff and this procedure, now in daily use since 2 years, assured proper histological and immuno-histochemical quality as well as RNA preservation (RIN values above 7). Fixation in PBF at controlled conditions improved RNA preservation and gene expression analysis of paraffin-embedded tissues.
Conclusions: Standardization of pre-analytical processing is mandatory for a proper preservation and processing of surgical biopsies. Their transfer in UVS assured standard quality for structural, antigenic and nucleic acids analysis.
Monday, February 28, 2011 1:00 PM
Poster Session II # 271, Monday Afternoon