title: Novel mutations of the HRAS gene and absence of hotspot mutations of             the BRAF genes in oral squamous cell carcinoma in a Greek population.
abstract: Oral squamous cell carcinoma (OSCC) is the sixth most common cancer in the             world. The phosphatidylinositol 3 kinase (PI3K) signalling pathway has been reported             to play an important role in OSCC. Since we have previously detected absence of             hotspot PIK3CA gene mutations in the Greek population, we hypothesized that BRAF             or HRAS may be activated as upstream effectors of the pathway. Furthermore, the             status of the HRAS and BRAF mutations in OSCC has never been assessed before in             the Greek population. Eighty-six primary paraffin-embedded tumors were screened             for BRAF and HRAS hotspot mutations. In HRAS, two hotspot mutations in codon 12             (2.3%) and eight new genetic alterations were detected (8.6% overall). One new             missense mutation, Alanine53Valine (Ala53Val), one silent mutation, two mutations             in the 5'UTR region and four mutations in intron 1 were detected. No hotspot mutations             in Braf were found. A new silent mutation/polymorphism T1803C was detected at             a percentage of 30%. This study is the first to report HRAS mutations in the Greek             population. The results suggest that RAS is an important member of the PI3K signalling             pathway and may play a role in the tumorigenesis of OSCC.
authors.affiliation: Second Department of Dermatology and Venereology, Medical School, Attikon University General Hospital, University of Athens, Athens, Greece. dkoumaki@yahoo.gr
authors.forename: Dimitra
authors.initials: D
authors.lastname: Koumaki
authors.forename: George
authors.initials: G
authors.lastname: Kostakis
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Koumaki
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Papadogeorgakis
authors.forename: Michael
authors.initials: M
authors.lastname: Makris
authors.forename: Alexandros
authors.initials: A
authors.lastname: Katoulis
authors.forename: Smaragda
authors.initials: S
authors.lastname: Kamakari
authors.forename: George
authors.initials: G
authors.lastname: Koutsodontis
authors.forename: Christos
authors.initials: C
authors.lastname: Perisanidis
authors.forename: Vaia
authors.initials: V
authors.lastname: Lambadiari
authors.forename: Evanthia
authors.initials: E
authors.lastname: Chrysomali
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Stavrianeas
authors.forename: Constantinos
authors.initials: C
authors.lastname: Alexandridis
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Rigopoulos
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D005260:Female; D006115:Greece; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000235:genetics* / Q000473:pathology; D009154:Mutation; D009367:Neoplasm Staging; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*; D044465:White People / Q000235:genetics
chemical_list: D048493:Proto-Oncogene Proteins B-raf; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras)