Usefulness of cytokeratin 5/6 and AMACR applied as double sequential immunostains for diagnostic assessment of problematic prostate specimens

Am J Clin Pathol. 2009 Aug;132(2):211-20; quiz 307. doi: 10.1309/AJCPGFJP83IXZEUR.

Abstract

We evaluated the usefulness of double immunohistochemical staining for cytokeratin (CK)5/6 and alpha-methylacyl coenzyme A racemase (AMACR) applied sequentially on 1 slide by assessing 223 foci in 110 consecutive prostate specimens. Double-chromogen reaction was used to visualize the antibodies: brown for CK5/6 and red for AMACR. Staining was scored as diffuse, focal, or negative. To establish the diagnosis, CK5/6 and AMACR were correlated with the morphologic features. All cancers lacked CK5/6 staining (100% specificity). AMACR showed diffuse or focal positivity in cancer, high-grade prostatic intraepithelial neoplasia, and atypia in 96.8% (120/124), 85% (22/26), and 80% (16/20) of cases, respectively. In atypical cases, diagnosis was because of non-immunohistochemical staining reasons in 80% of cases. In adenosis (n = 14), AMACR was diffusely positive in 4 cases (29%). Double immunohistochemical staining for CK5/6 and AMACR is a simple assay to perform and may be used as an alternative to antibody cocktails for routine evaluation of problematic prostate specimens.

MeSH terms

  • Biomarkers, Tumor / analysis
  • Humans
  • Immunohistochemistry / methods
  • Keratin-5 / metabolism*
  • Keratin-6 / metabolism*
  • Male
  • Prostatic Neoplasms / metabolism*
  • Racemases and Epimerases / metabolism*
  • Sensitivity and Specificity
  • Staining and Labeling / methods*

Substances

  • Biomarkers, Tumor
  • Keratin-5
  • Keratin-6
  • Racemases and Epimerases
  • alpha-methylacyl-CoA racemase