Against All Odds: RNA Extraction From Different Protocols Adapted to Formalin-fixed Paraffin-embedded Tissue.

Abstract

For the preservation of tissue samples, formalin fixation followed by paraffin embedding (FFPE) has been the method of choice for decades, mainly because it maintains the morphologic characteristics of the original tissue particularly preserved, as well as its genetic material. FFPE cells can be used to perform molecular tests, such as conventional (c) or quantitative (q) reverse transcriptase polymerase chain reaction (RT-PCR), in retrospective investigations. However, extracting RNA from archived FFPE tissues is a challenging procedure, as it requires time and the use of complex extraction methods. As specific FFPE extraction methods are not always available in the laboratories, the objective of this study was to evaluate the performance of a method based on phenol-chloroform (PC) and 2 commercial methods for RNA extraction, adapting their protocols for FFPE tissues. For this study, a pool of FFPE tissues underwent RNA extraction by PC, QIAmp Viral RNA Mini, and RNeasy Mini Kit. Both the RT-cPCR and the RT-qPCR results were favorable, demonstrating the viability of the RNA. As these results expanded the alternatives for low-budget FFPE extraction, the choice of the ideal method to be used will depend on the availability of reagents and kits.