title: Copy number amplification of the PIK3CA gene is associated with poor prognosis in non-lymph node metastatic head and neck squamous cell carcinoma.
abstract: BACKGROUND
  Deregulation of the EGFR signaling pathway is one of the most frequently observed genetic abnormalities that drives cancer development. Although mutations in the downstream components of the EGFR signaling pathway, including KRAS, BRAF and PIK3CA, have been reported in numerous cancers, extensive mutation and copy number analysis of these genes in clinical samples has not been performed for head and neck squamous cell carcinoma (HNSCC).
  
  
  METHODS
  We examined the mutations and copy number alterations of KRAS, BRAF and PIK3CA in 115 clinical specimens of HNSCC obtained from surgically treated patients.We used DNA sequencing to detect mutations and the copy number changes were evaluated by qPCR and array comparative genomic hybridization (CGH) analysis.
  
  
  RESULTS
  We examined the mutations and copy number alterations of KRAS, BRAF and PIK3CA in 115 clinical specimens of HNSCC obtained from surgically treated patients. We identified 3 mutations (2.6%) in K-RAS and 3 mutations (2.6%) in PIK3CA. Copy number amplification was found in 37 cases (32.2%) for PIK3CA, 10 cases (8.7%) for K-RAS and 2 cases (1.7%) for BRAF. Kaplan-Meier survival analysis revealed that copy-number amplification of PIK3CA was markedly associated with cancer relapse in patients without lymph node metastasis. (Log-rank test, p = 0.026)
  
  
  CONCLUSIONS
  Copy number amplification of the PIK3CA gene is associated with poor prognosis in HNSCC patients without lymph node metastasis. The PIK3CA copy number status will serve as a marker of poor prognosis in patients with HNSCC.
authors.affiliation: Department of Oto-Rhino-Laryngology, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors.forename: Toshihito
authors.initials: T
authors.lastname: Suda
authors.forename: Takanori
authors.initials: T
authors.lastname: Hama
authors.forename: Shu
authors.initials: S
authors.lastname: Kondo
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yuza
authors.forename: Mamoru
authors.initials: M
authors.lastname: Yoshikawa
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Urashima
authors.forename: Takakuni
authors.initials: T
authors.lastname: Kato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Moriyama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D058534:Class I Phosphatidylinositol 3-Kinases; D055028:Comparative Genomic Hybridization / Q000706:statistics & numerical data; D056915:DNA Copy Number Variations; D005260:Female; D005784:Gene Amplification; D006258:Head and Neck Neoplasms / Q000235:genetics* / Q000473:pathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009154:Mutation; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000235:genetics; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D060888:Real-Time Polymerase Chain Reaction / Q000706:statistics & numerical data; D000077195:Squamous Cell Carcinoma of Head and Neck; D018631:ras Proteins / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D019869:Phosphatidylinositol 3-Kinases; D058534:Class I Phosphatidylinositol 3-Kinases; C484760:PIK3CA protein, human; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins