Pancytokeratin

Pancytokeratin is a term pathologists use to describe a group of proteins called cytokeratins found within specific cells, particularly epithelial cells. Epithelial cells line surfaces inside and outside the body, including the skin and internal organs. Pancytokeratin tests detect many different types of cytokeratins at the same time.

Why do pathologists test for pancytokeratin?

Pathologists test for pancytokeratin to help identify and classify different types of cells seen under a microscope. It is particularly useful for distinguishing between cancers that start from epithelial cells (carcinomas) and cancers that originate from other cell types, such as lymphoma or sarcoma. By determining if cells are positive for pancytokeratin, pathologists can more accurately diagnose the type of tumour or disease present.

How do pathologists test for pancytokeratin?

Pathologists test for pancytokeratin using a method called immunohistochemistry. This technique involves applying special antibodies to a thin tissue section placed on a microscope slide. These antibodies specifically attach to pancytokeratin proteins if present. A chemical reaction then creates a colour change, making the pancytokeratin-positive cells visible under a microscope. This helps pathologists identify and classify the type of cells present in the tissue.

What types of normal cells and tissues will be positive for pancytokeratin?

Normal cells and tissues that express pancytokeratin include skin cells, cells lining the respiratory tract (lungs and airways), digestive tract (stomach and intestines), urinary tract, and reproductive organs. Pancytokeratin positivity is common in any normal tissue lined with epithelial cells. Pathologists describe these cells as “positive” when pancytokeratin is detected and “negative” when pancytokeratin is not detected.

What types of tumours will be positive for pancytokeratin?

Tumours originating from epithelial cells, known as carcinomas, typically test positive for pancytokeratin. Common examples include breast cancer, lung cancer, colon cancer, prostate cancer, and skin cancers such as squamous cell carcinoma. On the other hand, cancers that originate from blood cells (like lymphomas or leukaemias) or connective tissues (like sarcomas) usually test negative for pancytokeratin.