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Home > Technical section > Immunochemistry > Diagnostic antibodies > 34βE12


Sunday 12 January 2014


34βE12, often written as 34betaE12 and also known as CK34βE12 and keratin 903 (CK903), is an antibody specific for high molecular weight cytokeratins 1, 5, 10 and 14. It is sometimes, less precisely, referred to as high-molecular weight keratin (HMWK) and high-molecular weight cytokeratin (HMWCK).

Diagnostic use

- prostate cancer

  • It is used to stain basal cells in prostatic glands; loss of basal cells is seen in prostate adenocarcinoma (the most common form of prostate cancer).

- breast cancer

  • It can be used to differentiate in situ cancers of the breast; lobular carcinoma in situ (LCIS) exhibits perinuclear staining with 34βE12. Ductal carcinoma in situ (DCIS) does not stain for 34βE12.


- Aishima S, Asayama Y, Taguchi K, et al. (November 2002). "The utility of keratin 903 as a new prognostic marker in mass-forming-type intrahepatic cholangiocarcinoma". Mod. Pathol. 15 (11): 1181–90. doi : 10.1097/01.MP.0000032537.82380.69 PMID 12429797.

- Yeh IT, Mies C (March 2008). "Application of immunohistochemistry to breast lesions". Arch. Pathol. Lab. Med. 132 (3): 349–58. doi : 10.1043/1543-2165(2008)132[349:AOITBL]2.0.CO;2 PMID 18318578.