Alternative tissue fixation for combined histopathological and molecular analysis in a clinically representative
Amelia Meecham1, Elena Miranda1, Hayley T Morris2
1Research Department of Pathology, UCL Cancer Institute, London, UK.
Histochemistry and Cell Biology
|December 14, 2021
Summary
The PAXgene Tissue system offers superior preservation of DNA and RNA compared to formalin fixation. This non-formalin method maintains tissue morphology for diagnostics while enhancing nucleic acid quality for molecular analysis.
Area of Science:
- Biotechnology
- Histology
- Molecular Biology
Background:
- Formalin is the standard tissue fixative, preserving morphology but degrading DNA and RNA.
- Molecular diagnostics require high-quality nucleic acids, posing a challenge with formalin-fixed tissues.
Purpose of the Study:
- To evaluate the PAXgene Tissue system as a non-formalin alternative for tissue fixation.
- To assess its efficacy in preserving both tissue morphology and nucleic acid integrity for diagnostics.
Main Methods:
- A comparative study using 203 paired PAXgene Tissue and formalin-fixed samples.
- Evaluation of tissue morphology via haematoxylin and eosin (H&E) staining.
- Assessment of DNA and RNA quality using RIN and DIN scores, and performance in qPCR assays.
Main Results:
- PAXgene Tissue fixation showed comparable H&E staining to formalin.
- Immunohistochemistry (IHC) required minor optimization but was successful.
- Significantly improved DNA (DIN 5.68 vs 6.77) and RNA (RIN 2.8 vs 3.8) quality with PAXgene.
- Enhanced performance in qPCR assays using PAXgene-preserved nucleic acids.
Conclusions:
- The PAXgene Tissue system provides adequate histological staining and superior nucleic acid preservation compared to formalin.
- It is a viable alternative to formalin for routine use, especially in the genomic era.
- This method supports advanced molecular diagnostics alongside traditional techniques.
