title: Motility-related protein-1/CD9 expression in head and neck squamous cell carcinoma.
abstract: BACKGROUND
  Motility-related protein (MRP)-1/CD9 is implicated in cell adhesion and motility and was shown to be clearly involved in tumor prognosis and angiogenesis. Elevated MRP-1/CD9 expression on tumor cells has been linked to a favorable prognosis in breast cancer, colon cancer, lung cancer, and HNSCC. Because MRP-1/CD9 is associated with angiogenesis, it might play a role in tumor angiogenesis as well.
  
  
  METHODS
  We analyzed MRP-1/CD9 expression in HNSCC specimens and cell lines by real-time RT-PCR and in HNSCC biopsy specimens and stromal vessels by immunohistochemistry. Kruskal Wallis and Chi2 test, univariate and multivariate Cox regression, and Kaplan-Meier methods were used for statistical analysis.
  
  
  RESULTS
  Real-time and PCR RT showed elevated expression of MRP-1/CD9 in one (SCC25) of four HNSCC cell lines and two of six HNSCC patients, whereas two cell lines (SCC9 and JPPA) and one HNSCC patient had lower MRP-1/CD9 levels compared with other specimens. Immunohistochemistry demonstrated strong MRP-1/CD9 IR expression on tumor cells in 13 patients (39%), whereas 21 patients (61%) had less to medium MRP-1/CD9 IR expression. Increased MRP-1/CD9 expression on tumor cells was correlated with prolonged patient survival (p =.02) and a longer disease-free interval (p =.004), a diminished recurrence rate (p =.02), and lower stages of neck lymph nodes (p =.04). MRP-1/CD9 IR was also found in a subpopulation of vessels that seem to be less in tumor specimens than in normal mucosa (p <.0001). MRP-1/CD9+ vessels are podoplanin+ and are therefore regarded as lymphatic vessels.
  
  
  CONCLUSIONS
  Our results revealed that elevated MRP-1/CD9 expression on HNSCC is linked to a favorable clinical outcome and confirmed reports of MRP-1/CD9 expression in other carcinomas. MRP-1/CD9+ vessels were found to be lymphatic in nature. The number and staining intensity of these vessels is decreased in tumor tissue, which suggests a stabilizing role for this protein in lymphangiogenesis.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University of Vienna Medical School, Allgemeines Krankenhaus, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
authors.forename: Boban M
authors.initials: BM
authors.lastname: Erovic
authors.forename: Johannes
authors.initials: J
authors.lastname: Pammer
authors.forename: David
authors.initials: D
authors.lastname: Hollemann
authors.forename: Markus
authors.initials: M
authors.lastname: Woegerbauer
authors.forename: Silvana
authors.initials: S
authors.lastname: Geleff
authors.forename: Michael B
authors.initials: MB
authors.lastname: Fischer
authors.forename: Martin
authors.initials: M
authors.lastname: Burian
authors.forename: Florian
authors.initials: F
authors.lastname: Frommlet
authors.forename: Csilla
authors.initials: C
authors.lastname: Neuchrist
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis* / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000737:chemistry*; D002465:Cell Movement; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006258:Head and Neck Neoplasms / Q000737:chemistry*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000235:genetics; D008875:Middle Aged; D016016:Proportional Hazards Models; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D060245:Tetraspanin 29; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; C554869:CD9 protein, human; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D060245:Tetraspanin 29