AE1/AE3

The Pathology Dictionary Team
February 28, 2023

What are AE1/AE3?

AE1/AE3 are a pair of antibodies that recognize multiple cytokeratins, which are intermediate filament proteins that are found in epithelial cells. Cytokeratins are normally located in the cytoplasm (body) of the epithelial cell.

How is AE1/AE3 used in pathology?

AE1/AE3 staining is commonly used in diagnostic pathology to aid in the diagnosis and classification of tumours of epithelial origin, including carcinomas. Pathologists perform a test called immunohistochemistry to stain tissues for AE1/AE3 and the pattern and intensity of staining can help identify the presence of epithelial cells and differentiate them from non-epithelial cells.

What tumours are positive for AE1/AE3?

Most noncancerous and cancerous tumours that start from epithelial cells are positive for AE1/AE3. Cancerous tumours made up of epithelial cells are called carcinomas and they can be found anywhere in the body. Subtypes of carcinoma including adenocarcinoma and squamous cell carcinoma are also positive for AE1/AE3. Staining for AE1/AE3 helps pathologists distinguish carcinomas from other types of tumours that may look similar but do not make cytokeratins.

What does positive for AE1/AE3 mean?

Positive means that the cells in the tissue sample make cytokeratins.

What does negative for AE1/AE3 mean?

Negative means that the cells in the tissue sample do not make cytokeratins.

Are noncancerous tumours positive for AE1/AE3?

Yes. Many types of benign (noncancerous) tumours express cytokeratins and are positive for AE1/AE3. These types of noncancerous tumours are made up of epithelial cells that normally express cytokeratins.