Cytokeratin-18 Staining Method

**Semantic type:** Laboratory Procedure

**Definition:** An immunohistochemical technique to detect cytokeratin 18, an intermediate filament protein, using monoclonal antibody to cytokeratin 18. Specific combinations of cytokeratin peptides are associated with certain epithelial cells, and are therefore useful in the characterization of poorly differentiated carcinoma. The antibody reacts with a large number of epithelial cell types including many ductal and glandular epithelia. The test is used as a clinically significant indicator in distinguishing carcinoma from malignant tumors of non-epithelial origin, such as lymphoma, sarcoma, and melanoma.

**Synonyms:** - CK18 Staining Method - Cytokeratin 18 Staining Method - Keratin, Type I Cytoskeletal 18 Staining Method