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  • Preservation of nucleic acids and tissue morphology in paraffin-embedded clinical samples: comparison of five molecular fixatives.

Preservation of nucleic acids and tissue morphology in paraffin-embedded clinical samples: comparison of five molecular fixatives.

Journal of clinical pathology (2013-06-12)
Synnöve Staff, Paula Kujala, Ritva Karhu, Annika Rökman, Joanna Ilvesaro, Saara Kares, Jorma Isola
ABSTRACT

Formalin fixation preserves tissue morphology at the expense of macromolecule integrity. Freshly frozen samples are the golden standard for DNA and RNA analyses but require laborious deep-freezing and frozen sectioning for morphological studies. Alternative tissue stabilisation methods are therefore needed. We analysed the preservation of nucleic acids, immunohistochemical staining properties and tissue morphology in paraffin-embedded clinical tissue samples fixed with Z7, RCL2, PAXgene, Allprotect and RNAlater. Formalin-fixed and deep-frozen samples were used as controls. Immunohistochemical analyses showed good preservation of antigenicity in all except Allprotect and RNAlater-fixed samples. RNA quality, based on RNA integrity number value by Bioanalyzer, was comparable with freshly frozen samples only in PAXgene-fixed samples. According to quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses, RNA from PAXgene samples yielded results similar to freshly frozen samples. No difference between fixatives was seen in DNA analyses (PCR and real-time PCR). In conclusion, PAXgene seems to be superior to other molecular fixatives and formaldehyde.

MATERIALS
Product Number
Brand
Product Description

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