Encyclopedia of Experiments: Cancer Research
A subscription to JoVE is required to view this content.
Transcript
Formalin-fixed paraffin-embedding or FFPE technique allows the preservation of fixed, dehydrated, and cleared tissue specimens within paraffin blocks for long-term storage. FFPE preserves proteins and other vital intracellular components without compromising the tissue morphology.
Deparaffinization, or the removal of paraffin wax surrounding the embedded tissue, is a critical step before processing any FFPE tissue specimen for downstream analysis. To begin deparaffinization, start with a glass slide carrying an unstained FFPE tissue section of interest having an appropriate thickness.
Immerse the tissue section in a xylene bath and incubate for the desired duration. Xylene, an organic solvent, dissolves the paraffin wax that has embedded and penetrated the tissue. The complete removal of paraffin wax exposes the fixed and dehydrated transparent tissue specimen.
Following deparaffinization, treat the specimen with absolute ethanol. Ethanol displaces and removes any traces of xylene from the tissue section. Subsequently, immerse the tissue in decreasing concentrations of ethanol. The process rehydrates the tissue for downstream histological analysis.
Finally, leave the slide undisturbed for the desired duration. This step allows ethanol and water to evaporate and obtain a dry rehydrated tissue section.
