Cytokeratin, LMW (LCK)

LCK is a low-molecular-weight keratin that is expressed in almost all non-squamous epithelia, especially in a variety of single-layer tubular glandular epithelia. It is not expressed in squamous epithelium. CK-LMW can specifically label tumors arising from non-squamous epithelium. Ovarian adenocarcinoma, gastrointestinal adenocarcinoma, thyroid carcinoma and the vast majority of ductal carcinomas were marked. In particular, it showed positivity in epithelial tumors of the breast, pancreas, bile duct and salivary gland, tumors of endocrine organs (carcinoma and adenoma), liver cancer, endometrial cancer, renal cell carcinoma, neuroendocrine tumors and others. Bladder transitional cell carcinoma, nasopharyngeal carcinoma, thymoma and mesothelioma also showed positive reaction. The vast majority of squamous cell carcinomas were negative.