title: Absence of hotspot mutations in exons 9 and 20 of the PIK3CA gene in human oral squamous cell carcinoma in the Greek population.
abstract: OBJECTIVE
  Phosphatidylinositol-3 kinases (PI3K) are a group of heterodimeric lipid kinases that regulate many cellular processes. Recent studies have reported high frequencies of somatic hotspot mutations in the phosphatidylinositol-3 kinase catalytic alpha (PIK3CA) gene, which encodes for one of these kinases, in several human solid tumors, including oral squamous cell carcinoma (OSCC). The aim of this study was to determine the frequency of hotspot mutations in exons 9 and 20 of the PIK3CA gene in OSCC in the Greek population.
  
  
  METHODS
  Eighty-six formalin-fixed and paraffin-embedded primary tumor specimens were analyzed by direct genomic DNA sequencing. Chi-square was used for statistical analysis.
  
  
  RESULTS
  No hotspot mutations were detected in any of the samples. Two intronic polymorphisms IVS8 and IVS9 were detected, mainly in patients with cancer of the buccal mucosa and lower gingival and alveolus respectively.
  
  
  CONCLUSIONS
  PIK3CA hotspot mutations are unlikely to play a major role in the pathogenesis of OSCC in the Greek population.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Evagelismos Hospital, Dental School, University of Athens, Athens, Greece. kostakisgeorge@hotmail.com
authors.forename: George C
authors.initials: GC
authors.lastname: Kostakis
authors.forename: Nikos
authors.initials: N
authors.lastname: Papadogeorgakis
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Koumaki
authors.forename: Smaragda
authors.initials: S
authors.lastname: Kamakari
authors.forename: Dimitra
authors.initials: D
authors.lastname: Koumaki
authors.forename: Constantinos
authors.initials: C
authors.lastname: Alexandridis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000235:genetics; D016022:Case-Control Studies; D058534:Class I Phosphatidylinositol 3-Kinases; D003596:Cytosine; D005091:Exons / Q000235:genetics*; D005260:Female; D005887:Gingival Neoplasms / Q000201:enzymology / Q000235:genetics; D006115:Greece; D006147:Guanine; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D008339:Mandibular Neoplasms / Q000201:enzymology / Q000235:genetics; D008875:Middle Aged; D009061:Mouth Mucosa / Q000473:pathology; D009062:Mouth Neoplasms / Q000201:enzymology* / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D009367:Neoplasm Staging; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics; D017422:Sequence Analysis, DNA; D013941:Thymine; D014062:Tongue Neoplasms / Q000201:enzymology / Q000235:genetics; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D006147:Guanine; D003596:Cytosine; D019869:Phosphatidylinositol 3-Kinases; D058534:Class I Phosphatidylinositol 3-Kinases; C484760:PIK3CA protein, human; D013941:Thymine