Rapid microwave fixation of human tissues for light microscopic immunoperoxidase identification of diagnostically useful antigens.

Author(s): Login GR, Schnitt SJ, Dvorak AM

Publication: Lab Invest, 1987, Vol. 57, Page 585-91

PubMed ID: 3316839 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to compare microwave fixation in a dilute aldehyde mixture with immersion fixation in formalin with respect to the preservation of morphology and antigenicity in multiple tissue types, including skin, uterus, cervix, colon, and breast. Microwave irradiation was performed for 5-8 sec with a final solution temperature of 45 degrees C while formalin fixation was performed at room temperature for 6-8 h. Some microwave-fixed specimens were stored at 4 degrees C in physiological saline for up to 2 weeks before processing.

   Summary of Findings:

   Preservation of morphology was comparable between specimens that were fixed by microwaving in a 2% formaldehyde and 0.05% gluteraldehyde solution and those fixed by immersion in unbuffered formalin. However, the authors state that microwave-fixed specimens exhibited slightly more eosinophilia than formalin-fixed specimens. Epithelial membrane antigen (EMA), leukocyte common antigen (LCA), S-100 protein, and chromogranin (CG) immunostaining results were equivalent for the two fixation techniques. The authors state that storage of microwave-fixed specimens in saline for 2 weeks at 4 degrees C prior to paraffin embedding had no effects on immunostaining results. Trypsin digestion was necessary for carcinoembryonic antigen (CEA), factor VIII-related antigen (F-VIII), and keratin immunostaining of formalin-fixed specimens, but it was detrimental to immunostaining for microwave-fixed specimens. Epidermal keratin immunostaining was superior in untrypsinized microwave-fixed specimens compared to trypsinized formalin-fixed specimens.

   Biospecimens

   • Tissue - Skin
   • Tissue - Uterus
   • Tissue - Breast
   • Tissue - Colorectal
   • Tissue - Cervix

   Preservative Types

   • Formalin
   • Other Preservative

   Diagnoses:

   • Normal
   • Not specified

   Platform:

   Analyte	Technology Platform
   Morphology	H-and-E microscopy
   Protein	Immunohistochemistry

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Preservation	Type of fixation/preservation	Formalin (unbuffered) Gluteraldehyde-formaldehyde
   Biospecimen Preservation	Method of fixative delivery	Immersion Microwaved
   Immunohistochemistry Specific	Targeted peptide/protein	EMA LCA S-100 CG CEA F-VIII Keratin
   Analyte Extraction and Purification	Antigen retrieval	Trypsin None
   Storage	Storage duration	0 h 2 weeks

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