Cytokeratin 34 beta E12

Author: Kara Hamilton, M.S., Nat Pernick, M.D. (see Authors page)

Revised: 11 December 2015, last major update July 2013

Copyright: (c) 2003-2015,, Inc.

PubMed Search: 34betaE12
Cite this page: Cytokeratin 34 beta E12. website. Accessed March 22nd, 2018.
Definition / general
  • High molecular weight keratin relatively specific for prostate basal cells
  • Reacts to CK1, CK5, CK10 and CK14 and possibly other keratins
  • Also called CK903, high molecular weight keratin
Uses by pathologists
Microscopic (histologic) images

Images hosted on Pathout server:

Thyroid anaplastic carcinoma

Prostate: Normal

Images hosted on other servers:

Prostate: Basal cell hyperplasia

Prostate: Post-atrophic hyperplasia

Atypical adenomatous hyperplasia

Staining without and with antigen retrieval

High grade PIN: with adenocarcinoma

Prostatic adenocarcinoma is negative with occasional positive benign glands

Adenoid basal cell tumor

Low-grade bladder neoplasms

Images hosted on

Kidney: collecting duct carcinoma with signet ring features

Prostate: Atrophy with pseudoinfiltrative growth pattern

Prostate: Sclerosing adenosis

Atypical adenomatous hyperplasia

High grade PIN: #1-tufting pattern with 34BE12 staining; #2-micropapillary pattern; #3-flat pattern; #4-with foamy cytoplasm

Urothelial type adenocarcinoma with
mucin production is focally 34BE12+

Positive staining - normal
Positive staining - not malignant
Positive staining - malignant
Negative staining