Diagnostic and prognostic impact of cytokeratin 18 expression in human tumors: a tissue microarray study on 11,952 tumors

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 well 608 76 tissue were analyzed by immunohistochemistry a microarray format. Results was cells most organs but absent squamous epithelium. At least occasional weak positivity seen 90 (78.3%) types. Wide-spread 37 (31.9%) entities, including adenocarcinomas lung, prostate, colon pancreas ovarian cancer. Tumor categories with variable immunostaining included cancer arising positive precursor show downregulation fraction cases, negative occasionally exhibiting neo-expression, tumors derived expression, mixed differentiation. for example renal cell cancers breast cancers, whereas neo-expression found various origins. Down-regulation invasive no special clear (ccRCC) related to adverse features both (p ? 0.0001) poor patient prognosis ccRCC = 0.0088). Up-regulation linked high grade lymph node metastasis < 0.05). In summary, consistently especially adenocarcinomas. Conclusions loss originating progression may reflect dedifferentiation.