Cytokeratin AE1/AE3

AE1/3 is a broad‑spectrum cytokeratin immunohistochemical antibody cocktail used in IHC that combines two monoclonal clones, AE1 and AE3, which together detect a wide range of high and low‑molecular‑weight cytokeratins (CKs 1–8, 10, 14–16, and 19). It shows cytoplasmic and membranous staining in epithelial tissues and most carcinomas, making it valuable for confirming epithelial lineage in tumours. AE1/3 is commonly applied in assessing occult lymph node metastases, residual disease after neoadjuvant therapy, invasion depth, and tumour budding. It is typically used as part of an immunohistochemical panel rather than as a standalone stain (1).

Recommended Controls

Criteria for acceptable staining is membranous and cytoplasmic in tumour cells. Normal liver and appendix is recommended to be included as an in-house control. It should pick up on the membranes of the hepatocytes as well as on cells of epithelial origin. If a tumour tissue is included in the composite block, the expected staining expected staining is membranous and cytoplasmic in tumour cells, strong distinct cytoplasmic staining of all bile ductal epithelial cells and at least a moderate cytoplasmic staining with membrane accentuation of the vast majority of hepatocytes.

Expected staining pattern

Hepatocellular carcinoma

Lung Adenocarcinoma with normal lung

Appendix

Disclaimer

These methods are intended as a guide only. Laboratories that wish to implement these methods should perform internal validation/verification prior to use. The RCPAQAP does not make any claim or warranty for the accuracy or performance of these methods.