- Human pathology

Home > A. Molecular pathology > IHC markers > CK5/6


Friday 10 March 2017

See also : CK5 KRT5 / CK6 KRT6

Diagnostic use - Examples

- Usual ductal hyperplasia vs. DCIS

- Epitheliod mesothelioma vs. lung adenocarcinoma

- Has prognostic value when used with EGFR to determine if a triple negative breast carcinoma (ER-, PR-, Her2-) is expressing basal cell antigens (Basal-like breast carcinomas are CK5/6+ and EGFR+ and have a worse prognosis)

- Sinonasal Undifferentiated Carcinoma (SNUC) vs Squamous Cell Carcinoma (keratinizing and non-keratinizing types) in the sinonasal tract.

In the breast

- Differential diagnosis of breast DCIS vs epithelial hyperlasia

  • CK 5/6 may be a useful adjunct in the interpretation of problematic breast biopsies, where the distinction of DCIS or atypical hyperplasia from florid hyperplasia may be difficult on morphology alone.
  • >95% of cases of atypical ductal and lobular hyperplasia and DCIS were negative for CK 5/6, whereas areas of florid epithelial hyperplasia stained strongly.


- Expression of Cytokeratin 5/6 in Epithelial Neoplasms: An Immunohistochemical Study of 509 Cases. 2002.