Abstract Background Cytokeratin 18 (CK18) is an intermediate filament protein of the cytokeratin acidic type I group and primarily expressed in single-layered or “simple” epithelial tissues carcinomas different origin. Methods To systematically determine CK18 expression normal cancerous tissues, 11,952 tumor samples from 115 types subtypes (including carcinomas, mesenchymal biphasic tumors) as ...