Anti-Cytokeratin 20 Antibody

Cytokeratin 20 (KRT20) is a type I intermediate filament protein of roughly 46-50 kDa whose expression in normal tissue is strikingly restricted to gastrointestinal epithelium, urothelium, and Merkel cells. That narrow profile is what gives CK20 its diagnostic value, because tumors tend to retain the cytokeratin pattern of their tissue of origin. This unconjugated rabbit polyclonal reagent from Antibodies.com is raised against Cytokeratin 20 and is validated for western blot (WB), immunohistochemistry (IHC), and immunofluorescence (IF) on human samples. It is supplied in a 100 ul volume and is reactive with human KRT20, leaving the choice of secondary detection chemistry to the end user.

In surgical pathology the marker is most often deployed to work up metastatic adenocarcinoma of unknown primary, where a CK7-negative/CK20-positive profile supports a colorectal origin while a CK7-positive/CK20-positive profile is more typical of pancreatic, gastric, or some urothelial tumors. CK20 IHC is also a standard aid in identifying Merkel cell carcinoma, classically showing a paranuclear dot-like staining pattern that distinguishes it from small cell lung carcinoma. For western blot work, the antibody detects the expected ~46-50 kDa band, and the unconjugated format lets researchers pair it with HRP, fluorescent, or other labels of their choosing depending on the workflow.

The reagent is a polyclonal raised in rabbit, which can be helpful when a monoclonal clone gives ambiguous or absent staining on a particular preparation. As an unconjugated primary antibody it slots directly into established immunostaining, immunoblotting, and immunofluorescence protocols in most research histology and cell biology labs. The 100 ul pack size provides enough material for a substantial number of slides or blots when titrated appropriately for each application.