title: The phosphatase and tensin homologue deleted on chromosome 10 mediates radiosensitivity in head and neck cancer.
abstract: BACKGROUND
  For locally advanced squamous cell carcinoma of the head and neck (HNSCC), the recurrence rate after surgery and postoperative radiotherapy is between 20 and 40%, and the 5-year overall survival rate is approximately 50%. Presently, no markers exist to accurately predict treatment outcome. Expression of proteins in the human epidermal growth factor receptor (EGFR) pathway has been reported as a prognostic marker in several types of cancer.
  
  
  METHODS
  The aim of this study was to investigate the prognostic value of proteins in the EGFR pathway in HNSCC. For this purpose, we collected surgically resected tissue of 140 locally advanced head and neck cancer patients, all treated with surgery and postoperative radiotherapy.
  
  
  RESULTS
  In a multivariate analysis, expression of the phosphatase and tensin homologue deleted on chromosome 10 (PTEN) was significantly related to worse locoregional control (LRC; HR: 2.2, 95% CI: 1.1-4.6; P=0.03), independent of lymph node metastases (HR: 5.6, 95% CI: 1.2-27.4; P=0.03) and extranodal spread (HR: 2.7; 95% CI: 1.2-6.5; P=0.02). In vitro clonogenic radiosensitivity assays confirmed that overexpression of PTEN resulted in increased radioresistance.
  
  
  CONCLUSIONS
  Our study is the first report showing that expression of PTEN mediates radiosensitivity in vitro and that increased expression in advanced HNSCC predicts worse LRC.
authors.affiliation: Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: W J
authors.initials: WJ
authors.lastname: Pattje
authors.forename: E
authors.initials: E
authors.lastname: Schuuring
authors.forename: M F
authors.initials: MF
authors.lastname: Mastik
authors.forename: L
authors.initials: L
authors.lastname: Slagter-Menkema
authors.forename: M L
authors.initials: ML
authors.lastname: Schrijvers
authors.forename: S
authors.initials: S
authors.lastname: Alessi
authors.forename: B F A M
authors.initials: BF
authors.lastname: van der Laan
authors.forename: J L N
authors.initials: JL
authors.lastname: Roodenburg
authors.forename: J A
authors.initials: JA
authors.lastname: Langendijk
authors.forename: J E
authors.initials: JE
authors.lastname: van der Wal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000532:radiotherapy*; D002879:Chromosomes, Human, Pair 10; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D017353:Gene Deletion; D006258:Head and Neck Neoplasms / Q000235:genetics* / Q000532:radiotherapy*; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D051059:PTEN Phosphohydrolase / Q000235:genetics*; D011379:Prognosis; D011836:Radiation Tolerance / Q000235:genetics*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D014408:Biomarkers, Tumor; D066246:ErbB Receptors; D051059:PTEN Phosphohydrolase; D018719:Erb-b2 Receptor Tyrosine Kinases; C512478:EGFR protein, human; C508053:ERBB2 protein, human