Cytokeratin 14 expression in epithelial neoplasms: a survey of 435 cases with emphasis on its value in differentiating squamous cell carcinomas from other epithelial tumours.

The tissue distribution of cytokeratin 14 (CK14) in epithelial neoplasms is not well defined. We have evaluated 435 cases of epithelial neoplasm of various origins with cytokeratin 14 monoclonal antibody with special attention to possible use in differential diagnosis. Immunohistochemistry (ABC-HRP method) was performed for detection of CK14. We found that the expression of cytokeratin 14 was generally restricted to: (i) the majority of cases of squamous cell carcinoma regardless of origin (67/74) and degree of differentiation; (ii) neoplasms with focal squamous differentiation, including endometrial, and ovarian adenocarcinoma, malignant mesothelioma and transitional cell carcinoma; (iii) thymoma (8/8); (iv) myoepithelial components of salivary gland pleomorphic adenoma (3/4); and (v) oncocytic neoplasms, including thyroid Hurthle cell adenoma (1/1) and salivary gland Warthin's tumour (2/2). CK14 protein is a useful marker in differential diagnosis of squamous cell carcinomas.