NIH, National Cancer Institute, Division of Cancer Treatment and Diagnosis (DCTD) NIH - National Institutes of Health National Cancer Institute DCTD - Division of Cancer Treatment and Diagnosis

Ultrasound-accelerated Tissue Fixation/Processing Achieves Superior Morphology and Macromolecule Integrity with Storage Stability

Author(s): Chu Wei-Sing, Liang Qi, Tang Yao, King Randy, Wong Kondi, Gong Maokai, Wei Minqi, Liu Jilan, Feng Shaw-Huey, Lo Shyh-Ching, Andriko Jo-Ann, Orr Marshall

Publication: J Histochem Cytochem, 2006, Vol. 54, Page 503

PubMed ID: 16314441 PubMed Review Paper? No

Purpose of Paper

To assess the long-term stability of histological and molecular antigens isolated from tissue fixed by ultrasound accelerated formalin fixation (USAFF) and processing and storage at room temperature.

Conclusion of Paper

USAFF tissues resulted in superior tissue morphology, protein antigenicity, and RNA stability in comparison to conventional formalin fixation. Prolonged storage of USAFF paraffin blocks (7 years) did not significantly impact tissue morphology, protein antigenicity, or nucleic acid levels or localization.

Studies

  1. Study Purpose

    To determine if USAFF and processing compromises the stability of cellular morphology or protein antigenicity after prolonged storage of paraffin blocks at room temperature.

    Summary of Findings:

    No differences in cellular structure or preservation were observed in USAFF tissue as compared to conventional formalin fixed paraffin embedded tissue, as determine by microscopic analysis. Immunostaining revealed USAFF tissue yielded superior staining, required less primary antibody, and antigen retrieval was often unnecessary in comparison to conventional formalin fixation. Further, a shortened staining protocol could be employed with USAFF tissue. Storage of USAFF paraffin tissue blocks for up to 7 years did not affect immunohistochemical staining, indicating stability was preserved.

    Biospecimens
    Preservative Types
    • Formalin
    Diagnoses:
    • Autopsy
    • Not specified
    Platform:
    AnalyteTechnology Platform
    Protein Immunohistochemistry
    Morphology H-and-E microscopy
    Pre-analytical Factors:
    ClassificationPre-analytical FactorValue(s)
    Biospecimen Preservation Method of fixative delivery Immersion
    Ultrasound-accelerated
  2. Study Purpose

    To determine if USAFF and processing compromises RNA stability after prolonged storage of paraffin blocks at room temperature. In situ hybridization of kappa light chain immunoglobulin mRNA was compared among specimens freshly preserved by conventional formalin fixation and USAFF as well as USAFF tissue blocks after 7 years of storage at room temperature.

    Summary of Findings:

    Prolonged storage of USAFF paraffin blocks did not impact in situ hybridization results. Further, USAFF specimens stored for seven years displayed uniform and appropriate signal location, while signals in specimens freshly fixed by conventional methods were sporadic and limited to the periphery of the tissue section.

    Biospecimens
    Preservative Types
    • Formalin
    Diagnoses:
    • Not specified
    • Autopsy
    Platform:
    AnalyteTechnology Platform
    RNA In situ hybridization
    Pre-analytical Factors:
    ClassificationPre-analytical FactorValue(s)
    Biospecimen Preservation Method of fixative delivery Ultrasound-accelerated
    Immersion
  3. Study Purpose

    To determine if USAFF or long term storage of paraffin tissue blocks compromises the level of extracted DNA.

    Summary of Findings:

    Although greater DNA concentrations were observed in USAFF tissue compared to conventional formalin fixation, the abundance and success of PCR products were dependent on amplicon size, with larger amplicons requiring a higher cycle number and a complete lack of large (1 kb) products for all formalin fixed tissue.

    Biospecimens
    Preservative Types
    • Formalin
    • Frozen
    Diagnoses:
    • Not specified
    • Autopsy
    Platform:
    AnalyteTechnology Platform
    DNA PCR
    Pre-analytical Factors:
    ClassificationPre-analytical FactorValue(s)
    PCR Specific Targeted nucleic acid beta-actin
    PCR Specific Length of gene fragment 220 bp
    489 bp
    811 bp
    1062 bp
    647 bp
    Biospecimen Preservation Method of fixative delivery Immersion
    Ultrasound-accelerated
    Biospecimen Preservation Type of fixation/preservation Formalin (buffered)
    Snap frozen
  4. Study Purpose

    To determine if USAFF or long term storage of paraffin tissue blocks compromises RNA expression levels.

    Summary of Findings:

    Similar to DNA results, mRNA expression levels were dependent on the length of the generated amplicon, with a higher PCR success rate observed with shorter amplicons. After prolonged storage, conventionally fixed tissue and USAFF tissue yielded comparable results that were inferior to frozen tissue, as observed by semi-quantitative RT-PCR. However, real time quantitative RT-PCR analysis showed that a larger quantity of relative RNA was present in frozen tissue, followed by ultrasound accelerated formalin fixed tissue, then conventional formalin fixed tissue.

    Biospecimens
    Preservative Types
    • Formalin
    • Frozen
    Diagnoses:
    • Not specified
    • Autopsy
    Platform:
    AnalyteTechnology Platform
    RNA RT-PCR
    RNA Real-time qRT-PCR
    Pre-analytical Factors:
    ClassificationPre-analytical FactorValue(s)
    RT-PCR Specific Targeted nucleic acid beta-actin
    RT-PCR Specific Length of gene fragment 220 bp
    489 bp
    811 bp
    Biospecimen Preservation Method of fixative delivery Immersion
    Ultrasound-accelerated
    Biospecimen Preservation Type of fixation/preservation Formalin (buffered)
    Snap frozen

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