title: Proteomic analysis of protein expression in human tonsillar cancer: differentially expressed proteins characterize human tonsillar cancer.
abstract: BACKGROUND
  Head and neck cancer continues to be one of the most common tumor entities worldwide. Within this group of malignancies, tonsillar squamous cell carcinoma represent approximately 15-20% of all intraoral and oropharyngeal carcinomas in the United States. Accurate and early stage diagnosis still remains a major challenge, as patients are often presented at an advanced stage of disease, causing a low overall survival rate. Thus, new diagnostic markers are highly desirable and could allow for a more reliable diagnosis, with further insights into carcinogenesis and tumor biology. Furthermore, these markers could be the basis for new therapeutic targets and early disease detection. To address these issues, we decided to use a global proteomic approach to characterize tonsillar squamous cell carcinoma.
  
  
  METHODS
  A total of 19 tonsillar carcinoma samples and 12 benign controls acquired from the corresponding normal epithelium were analyzed by 2-D gel electrophoresis. 2-DE gels were silver stained and analyzed using the PDQuest analysis software (BioRad). Tumor specific spots were detected and identified by consecutive MALDI-TOF-MS or MS/MS polypeptide identification.
  
  
  RESULTS
  In total, 70 proteins showed significant quantitative differences in protein expression, with 50 polypeptides accessible for identification. Of those 50 polypeptides, we were able to identify a total of 27 proteins and protein isoforms, significantly up- or down-regulated in tonsillar cancer samples. In addition to previously reported polypeptides in head and neck cancers, we were able to identify several new potential marker proteins in this study.
  
  
  CONCLUSIONS
  Our results show that a combination of tonsillar cancer specific proteins can be used for histopathological diagnosis and may serve as a basis for discovering further biomarkers for early detection and prediction of response to treatment in the future.
authors.affiliation: Department of Surgery and Laboratory for Surgical Research, University of Schleswig-Holstein, Luebeck, Germany.
authors.forename: Uwe J
authors.initials: UJ
authors.lastname: Roblick
authors.forename: Franz G
authors.initials: FG
authors.lastname: Bader
authors.forename: Lalle
authors.initials: L
authors.lastname: Hammarstedt
authors.forename: Jens K
authors.initials: JK
authors.lastname: Habermann
authors.forename: Ulf
authors.initials: U
authors.lastname: Hellman
authors.forename: Susanne
authors.initials: S
authors.lastname: Becker
authors.forename: Axel
authors.initials: A
authors.lastname: Sundmacker
authors.forename: Timo
authors.initials: T
authors.lastname: Gemoll
authors.forename: Kaja
authors.initials: K
authors.lastname: Zimmermann
authors.forename: Gert
authors.initials: G
authors.lastname: Auer
authors.forename: Eva
authors.initials: E
authors.lastname: Munck-Wikland