EP4 or BerEP4 is a cell surface glycoprotein and is broadly distributed in epithelial cells and displays a highly conserved expression in carcinomas. EP4 is very useful in the differentation of adenocarcinoma from mesothelioma. EP4 is tumor-cell marker in lymph nodes from patients with oesophageal carcinoma. EP4 is particularly useful in differentiation of basal cell which is positive from squamous cell carcinoma negative. Expressed in almost all epithelial cell membranes but not on mesodermal or neural cell membranes. Found on the surface of adenocarcinoma.

The staining pattern of EP4 is Membraneous and Cytoplasmic as shown below.

Picture 1 – EP4 positivity in Breast Carcinoma

 

EP4 has several different applications. Below are a few examples.

Tumour or cell type	EP4 + or -
Pulmonary Adenocarcinoma	Positive
Breast Carcinoma	Positive
Basal Cell Carcinoma	Positive
Mesothelioma	Negative