Keratin, type I cytoskeletal 20 (KRT20)

Keratin, type I cytoskeletal 20 (KRT20), also known as Cytokeratin-20 (CK20), is a type I intermediate filament protein primarily expressed in the intestinal epithelium, gastric foveolar epithelium, and Merkel cells (UniProt P35900). It plays a fundamental role in maintaining the structural integrity and mechanical stability of the cytoskeleton in these specific epithelial cells (PubMed: 15215059). In clinical oncology, KRT20 is a cornerstone diagnostic biomarker used in immunohistochemistry to determine the origin of metastatic adenocarcinomas; for instance, a CK20+/CK7- phenotype is highly indicative of a colorectal primary (PubMed: 10548371). While it is not currently utilized as a direct therapeutic target for small molecules or antibodies due to its intracellular location and structural function, it is frequently used for patient stratification and monitoring minimal residual disease in colorectal cancer (PubMed: 22535153). Experimental approaches have explored KRT20 as a tumor-associated antigen for immunotherapy, such as cancer vaccines or T-cell therapies, though no such treatments are currently approved for clinical use (PubMed: 11861267). Its high specificity for certain tissues makes it an ideal marker for identifying micrometastases in lymph nodes and peripheral blood (PubMed: 12118105). Overall, KRT20 remains one of the most important tools in the pathologist's arsenal for cancer characterization and management.

Other names

Cytokeratin-20CK20K20Keratin-20Protein IT

Not applicable; KRT20 is a structural protein and diagnostic biomarker, not a direct therapeutic target for currently approved drugs.