BMC Cancer 2006, 6:165 http://www.biomedcentral.com/1471-2407/6/165 nosis of esophageal SCC patients. This is particularly suggested in the adjuvant situation, since the population of minimal residual tumor cells is considered to be more amenable to antibody-based therapies, compared to large tumour masses in advanced stages of cancer [43]. Conclusion In conclusion, our results suggest Ep-CAM as an attractive molecule for targeted therapy in esophageal SCC, espe- cially in the adjuvant situation. Considering the discon- tenting results of the current adjuvant concepts for esophageal SCC patients, anti-body based therapy directed against Ep-CAM holds promise for more effective eradication of minimal residual cancer to suppress lethal metastatic disease. Competing interests The author(s) declare that they have no competing inter- ests. Authors' contributions NHS, SBH and WTK designed and coordinated the study, interpreted the data and wrote the manuscript. AS, AML and NHS performed and evaluated the immunohisto- chemical analysis. AS, PS and AR contributed substan- tially to the data acquisition and drafting the manuscript. AE was responsible for the histopathological evaluation, reviewed the cases and revised the manuscript critically. PEV contributed to and supervised the statistical analysis. CFE was involved in the sample acquisition, sample selec- tion, clinical data acquisition and preparing the manu- script, MP and JSAE contributed to the acquisition and interpretation of the data and revised the manuscript crit- ically. All authors read and approved the final version of the manuscript. References Enzinger PC, Mayer RJ: Esophageal cancer. N Engl J Med 2003, 349(23):2241-2252. Jemal A, Murray T, Ward E, Samuels A, Tiwari RC, Ghafoor A, Feuer EJ, Thun MJ: Cancer statistics, 2005. CA Cancer J Clin 2005, 55(1):10-30. Greer SE, Goodney PP, Sutton JE, Birkmeyer JD: Neoadjuvant chemoradiotherapy for esophageal carcinoma: a meta-anal- ysis. Surgery 2005, 137(2):172-177. Malthaner RA, Wong RK, Rumble RB, Zuraw L: Neoadjuvant or adjuvant therapy for resectable esophageal cancer: a clinical practice guideline. BMC Cancer 2004, 4(1):67. Malthaner RA, Wong RK, Rumble RB, Zuraw L: Neoadjuvant or adjuvant therapy for resectable esophageal cancer: a sys- tematic review and meta-analysis. BMC Med 2004, 2(1):35. Linnenbach AJ, Pressler LB, Seng BA, Kimmel BS, Tomaszewski JE, Malkowicz SB: Characterization of chromosome 9 deletions in transitional cell carcinoma by microsatellite assay. Hum Mol Genet 1993, 2(9):1407-1411. Spurr NK, Durbin H, Sheer D, Parkar M, Bobrow L, Bodmer WF: Characterization and chromosomal assignment of a human cell surface antigen defined by the monoclonal antibody AUAI. Int J Cancer 1986, 38(5):631-636. Calabrese G, Crescenzi C, Morizio E, Palka G, Guerra E, Alberti S: Assignment of TACSTD1 (alias TROP1, M4S1) to human chromosome 2p21 and refinement of mapping of TACSTD2 1. 2. 3. 4. 5. 6. 7. 8. (alias TROP2, M1S1) to human chromosome 1p32 by in situ hybridization. Cytogenet Cell Genet 2001, 92(1-2):164-165. 9. Litvinov SV, Bakker HA, Gourevitch MM, Velders MP, Warnaar SO: Evidence for a role of the epithelial glycoprotein 40 (Ep- CAM) in epithelial cell-cell adhesion. Cell Adhes Commun 1994, 2(5):417-428. 10. Litvinov SV, Balzar M, Winter MJ, Bakker HA, Briaire-de Bruijn IH, Prins F, Fleuren GJ, Warnaar SO: Epithelial cell adhesion mole- cule (Ep-CAM) modulates cell-cell interactions mediated by classic cadherins. J Cell Biol 1997, 139(5):1337-1348. 11. Litvinov SV, Velders MP, Bakker HA, Fleuren GJ, Warnaar SO: Ep- CAM: a human epithelial antigen is a homophilic cell-cell adhesion molecule. J Cell Biol 1994, 125(2):437-446. 12. Balzar M, Bakker HA, Briaire-de-Bruijn IH, Fleuren GJ, Warnaar SO, Litvinov SV: Cytoplasmic tail regulates the intercellular adhe- sion function of the epithelial cell adhesion molecule. Mol Cell Biol 1998, 18(8):4833-4843. 13. Balzar M, Winter MJ, de Boer CJ, Litvinov SV: The biology of the 17-1A antigen (Ep-CAM). J Mol Med 1999, 77(10):699-712. 14. Winter MJ, Nagtegaal ID, van Krieken JH, Litvinov SV: The epithelial cell adhesion molecule (Ep-CAM) as a morphoregulatory molecule is a tool in surgical pathology. Am J Pathol 2003, 163(6):2139-2148. 15. Gastl G, Spizzo G, Obrist P, Dunser M, Mikuz G: Ep-CAM overex- pression in breast cancer as a predictor of survival. Lancet 2000, 356(9246):1981-1982. 16. Spizzo G, Went P, Dirnhofer S, Obrist P, Simon R, Spichtin H, Maurer R, Metzger U, von Castelberg B, Bart R, Stopatschinskaya S, Kochli OR, Haas P, Mross F, Zuber M, Dietrich H, Bischoff S, Mirlacher M, Sauter G, Gastl G: High Ep-CAM expression is associated with poor prognosis in node-positive breast cancer. Breast Cancer Res Treat 2004, 86(3):207-213. 17. Varga M, Obrist P, Schneeberger S, Muhlmann G, Felgel-Farnholz C, Fong D, Zitt M, Brunhuber T, Schafer G, Gastl G, Spizzo G: Overex- pression of epithelial cell adhesion molecule antigen in gall- bladder carcinoma is an independent marker for poor survival. Clin Cancer Res 2004, 10(9):3131-3136. 18. Armstrong A, Eck SL: EpCAM: A new therapeutic target for an old cancer antigen. Cancer Biol Ther 2003, 2(4):320-326. 19. Heiss MM, Strohlein MA, Jager M, Kimmig R, Burges A, Schoberth A, Jauch KW, Schildberg FW, Lindhofer H: Immunotherapy of malig- nant ascites with trifunctional antibodies. Int J Cancer 2005, 117(3):435-443. 20. Schmitt M, Schmitt A, Reinhardt P, Thess B, Manfras B, Lindhofer H, Riechelmann H, Wiesneth M, Gronau S: Opsonization with a tri- functional bispecific (alphaCD3 x alphaEpCAM) antibody results in efficient lysis in vitro and in vivo of EpCAM positive tumor cells by cytotoxic T lymphocytes. Int J Oncol 2004, 25(4):841-848. 21. Stemmler HJ, Salat C, Lindhofer H, Menzel H, Untch M, Kahlert S, Konecny G, Sauer H, Ledderose G, Heinemann V, Kolb HJ: Com- bined treatment of metastatic breast cancer (MBC) by high- dose chemotherapy (HDCT) and bispecific antibodies: a pilot study. Anticancer Res 2005, 25(4):3047-3054. 22. UICC - TNM Classification of Malignant Tumours. 5th edi- tion. Edited by: Sobin LH, Wittekind C. New York , Wiley-Liss; 1997. 23. Hosch SB, Stoecklein NH, Pichlmeier U, Rehders A, Scheunemann P, Niendorf A, Knoefel WT, Izbicki JR: Esophageal cancer: the mode of lymphatic tumor cell spread and its prognostic sig- nificance. J Clin Oncol 2001, 19(7):1970-1975. 24. Schwarz G: Estimating the dimension of a model. Annals of Sta- tistics 1978, 6:461-464. 25. Volinsky CT, Raftery AE: Bayesian information criterion for censored survival models. Biometrics 2000, 56(1):256-262. 26. Burnham K, Anderson DR: Model Selection and Multimodel inference: a practical information-theoretic approach. 2nd edition. New York , Springer; 2002. 27. R, Developement, Core, Team: R: A language and environment for statistical computing. Vienna , R Foundation for Statistical Computing; 2004. 28. Piyathilake CJ, Frost AR, Weiss H, Manne U, Heimburger DC, Grizzle WE: The expression of Ep-CAM (17-1A) in squamous cell cancers of the lung. Hum Pathol 2000, 31(4):482-487. 29. Hosch SB, Scheunemann P, Izbicki JR: Minimal residual disease in non-small-cell lung cancer. Semin Surg Oncol 2001, 20(4):278-281. Page 7 of 8 (page number not for citation purposes)