Antigen retrieval technique utilizing citrate buffer or urea solution for immunohistochemical demonstration of androgen receptor in formalin-fixed paraffin sections.

Author(s): Shi SR, Chaiwun B, Young L, Cote RJ, Taylor CR

Publication: J Histochem Cytochem, 1993, Vol. 41, Page 1599

PubMed ID: 7691930 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to conduct a comparative assessment of nuclear AR immunostaining in FFPE (fixed for 1-7 d) and frozen tissue sections following microwave heating, enzyme digestion, or acid antigen retrieval approaches. Tissues examined included prostate, breast, colon, lung, and stomach.

   Summary of Findings:

   The authors report that optimal androgen receptor visualization with the lowest background was obtained in microwave-heated, dewaxed sections after pretreatment with pH 6.0, 5% urea or citrate buffer. This was superior to pretreatment with saturated lead thiocyanate followed by microwave heating, and was qualitatively and quantitatively comparable to immunolocalization of androgen receptor in case-matched frozen biospecimens. Results held true for sections fixed for 24 hours or seven days. Enzymatic pretreatment with pepsin (5 min at 37 degrees C or 30 min at room temperature), trypsin (10 min at 37 degrees C), pronase E (5 min at 37 degrees C), trypsin and pronase E (sequentially for 5 min each at 37 degrees C) with no microwave heating resulted in less consistent staining and higher background.

   Biospecimens

   • Tissue - Prostate
   • Tissue - Stomach
   • Tissue - Lung
   • Tissue - Breast
   • Tissue - Colorectal

   Preservative Types

   • Formalin
   • OCT

   Diagnoses:

   • Neoplastic - Carcinoma
   • Not specified

   Platform:

   Analyte	Technology Platform
   Protein	Immunohistochemistry

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Preservation	Type of fixation/preservation	Formalin (buffered) OCT
   Biospecimen Preservation	Time in fixative	24 h 7 d
   Analyte Extraction and Purification	Temperature of heat-induced retrieval	Room temperature 37 degrees C Microwave heating
   Analyte Extraction and Purification	Antigen retrieval	5% urea + microwave heating 5% citrate + microwave heating Saturate lead thiocyanate + microwave heating 0.05% Pepsin/2N HCl 0.025% Trypsin/PBS 0.025% Pronase 0.1% Dnase 0.05% Protease 5 min incubation 10 min incubation 30 min incubation

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