Steam heat with an EDTA buffer and protease digestion optimizes immunohistochemical expression of basal cell-specific antikeratin 34/βE12 to discriminate cancer in prostatic epithelium

Kenneth A. Iczkowski, Liang Cheng, Barbara G. Crawford, David G. Bostwick

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20 Scopus citations


In select cases of prostatic carcinoma, antikeratin 34βE12 immunohistochemical analysis is diagnostically useful for specific labeling of basal cells. This antibody, however, is prone to variability in staining, and the optimal conditions were not, to our knowledge, previously defined. We combined steam heat with EDTA buffer (steam-EDTA) and protease digestion (steam-EDTA + protease) to optimize epitope retrieval of antikeratin 34βE12 in 42 cases of prostatic cancer. Results were judged by the percentage of cells staining and by staining intensity. In benign epithelium, steam-EDTA + protease significantly increased the percentage of immunoreactive cells (from 74 to 93%) and the intensity of staining (from 2.1 to 3.0 on a scale of 0- 3+) by comparison with protease alone (all P < .001). In high-grade prostatic intraepithelial neoplasia, the percentage of cells staining increased from 55 to 73% and intensity increased from 1.7 to 2.8 (both P < .001). Steam-EDTA + protease also minimized variability in results between cases, with essentially no background stromal staining. Cancer was negative in all of our cases by both methods. We conclude that steam-EDTA + protease significantly enhances basal cell immunoreactivity compared with protease treatment alone in noncancerous prostatic epithelium. This helps to prevent misinterpretation of histologic mimics of cancer, such as atrophic acini and high-grade prostatic intraepithelial neoplasia, that result from false-negative staining.

Original languageEnglish (US)
Pages (from-to)1-4
Number of pages4
JournalModern Pathology
Issue number1
StatePublished - Jan 1999
Externally publishedYes



  • Basal cells
  • Cytokeratin
  • Epitope retrieval
  • Immunohistochemistry
  • Intermediate filaments
  • Prostatic neoplasms
  • Steam heat

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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