BMC Cancer Research article Cytokeratin 8/18 expression indicates a poor prognosis in squamous cell carcinomas of the oral cavity Thomas Fillies*1, Richard Werkmeister2, Jens Packeisen3, Burkhard Brandt4, Philippe Morin5, Dieter Weingart5, Ulrich Joos1 and Horst Buerger6 BioMed Central Open Access Address: 1Department of Cranio-Maxillofacial Surgery, University of Muenster, Waldeyerstrasse 30, 48129 Muenster, Germany, 2Department of Oral and Maxillofacial Surgery, Central German Armed Forces Hospital, Rübenacher Str. 170, 56072 Koblenz, Germany, 3Institute of Pathology, Klinikum Osnabrueck, Germany, 4Institute of Tumor Biology, Center of Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20146 Hamburg, Germany, 5Department of Maxillofacial Surgery, Katharinenhospital Stuttgart, Kriegsbergstrasse 60, 70174 Stuttgart, Germany and 6Institute of Pathology, University of Muenster, Domagkstraβe 17, 48149 Muenster, Germany Email: Thomas Fillies* - fillies@uni-muenster.de; Richard Werkmeister - Rwerkmeis@aol.com; Jens Packeisen - jpackeisen@pathoweb.de; Burkhard Brandt - bu.brandt@uke.uni-hamburg.de; Philippe Morin - p.morin@katharinenhospital.de; Dieter Weingart - weingart.mkg@katharinenhospital.de; Ulrich Joos - joos@uni-muenster.de; Horst Buerger - burgerh@uni-muenster.de * Corresponding author Published: 13 January 2006 BMC Cancer 2006, 6:10 doi:10.1186/1471-2407-6-10 This article is available from: http://www.biomedcentral.com/1471-2407/6/10 Received: 11 May 2005 Accepted: 13 January 2006 © 2006 Fillies et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background: Intermediary filaments are involved in cell motility and cancer progression. In a variety of organs, the expression of distinct intermediary filaments are associated with patient prognosis. In this study, we seeked to define the prognostic potential of cytokeratin and vimentin expression patterns in squamous cell carcinomas (SCC's) of the oral cavity. Methods: 308 patients with histologically proven and surgically treated squamous cell carcinomas of the oral cavity were investigated for the immunohistochemical expression of a variety of intermediary filaments including high- and low-molecular weight cytokeratins (Ck's), such as Ck 5/ 6, Ck 8/18, Ck 1, CK 10, Ck 14, Ck 19 and vimentin, using the tissue microarray technique. Correlations between clinical features and the expression of Cytokeratins and vimentin were evaluated statistically by Kaplan-Meier curves and multivariate Cox regression analysis. Results: The expression of Ck 8/18 and Ck 19 were overall significantly correlated with a poor clinical prognosis (Ck 8/18 p = 0.04; Ck19 p < 0.01). These findings could also be reproduced for Ck 8/18 in primary nodal-negative SCC's and held true in multivariate-analysis. No significant correlation with patient prognosis could be found for the expression of the other cytokeratins and for vimentin. Conclusion: The expression of Ck 8/18 in SCC's of the oral cavity is an independent prognostic marker and indicates a decreased overall and progression free survival. These results provide an extended knowledge about the role of intermediary filament expression patterns in SCC's. Background Intermediary filaments, like cytokeratins are essential intracellular components, underlying or reflecting distinct cellular properties and differentiation stages in epithelial organs. The proteins of the cytokeratin family are epithe- lium specific expressed [1] as low and high-molecular Page 1 of 8 (page number not for citation purposes)