title: Epidermal growth factor receptor and K-RAS status in two cohorts of squamous cell carcinomas.
abstract: BACKGROUND
  With the availability of effective anti-EGFR therapies for various solid malignancies, such as non-cell small lung cancer, colorectal cancer and squamous cell carcinoma of the head and neck, the knowledge of EGFR and K-RAS status becomes clinically important. The aim of this study was to analyse EGFR expression, EGFR gene copy number and EGFR and K-RAS mutations in two cohorts of squamous cell carcinomas, specifically anal canal and tonsil carcinomas.
  
  
  METHODS
  Formalin fixed, paraffin-embedded tissues from anal and tonsil carcinoma were used. EGFR protein expression and EGFR gene copy number were analysed by means of immunohistochemistry and fluorescence in situ hybridisation. The somatic status of the EGFR gene was investigated by PCR using primers specific for exons 18 through 21. For the K-RAS gene, PCR was performed using exon 2 specific primers.
  
  
  RESULTS
  EGFR immunoreactivity was present in 36/43 (83.7%) of anal canal and in 20/24 (83.3%) of tonsil squamous cell carcinomas. EGFR amplification was absent in anal canal tumours (0/23), but could be identified in 4 of 24 tonsil tumours.From 38 anal canal specimens, 26 specimens were successfully analysed for exon 18, 30 for exon 19, 34 for exon 20 and 30 for exon 21. No EGFR mutations were found in the investigated samples. Thirty samples were sequenced for K-RAS exon 2 and no mutation was identified. From 24 tonsil specimens, 22 were successfully analysed for exon 18 and all 24 specimens for exon 19, 20 and 21. No EGFR mutations were found. Twenty-two samples were sequenced for K-RAS exon 2 and one mutation c.53C > A was identified.
  
  
  CONCLUSIONS
  EGFR mutations were absent from squamous cell carcinoma of the anus and tonsils, but EGFR protein expression was detected in the majority of the cases. EGFR amplification was seen in tonsil but not in anal canal carcinomas. In our investigated panel, only one mutation in the K-RAS gene of a tonsil squamous cell carcinoma was identified. This indicates that EGFR and K-RAS mutation analysis is not useful as a screening test for sensitivity to anti-EGFR therapy in anal canal and tonsil squamous cell carcinoma.
authors.affiliation: Department of Hepato-Gastroenterology, Digestive Oncology Unit, Ghent University Hospital, De Pintelaan 185 1K12IE, 9000 Ghent, Belgium. nancy.vandamme@ugent.be
authors.forename: Nancy
authors.initials: N
authors.lastname: Van Damme
authors.forename: Philippe
authors.initials: P
authors.lastname: Deron
authors.forename: Nadine
authors.initials: N
authors.lastname: Van Roy
authors.forename: Pieter
authors.initials: P
authors.lastname: Demetter
authors.forename: Alain
authors.initials: A
authors.lastname: Bols
authors.forename: Jo
authors.initials: J
authors.lastname: Van Dorpe
authors.forename: Filip
authors.initials: F
authors.lastname: Baert
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Van Laethem
authors.forename: Franki
authors.initials: F
authors.lastname: Speleman
authors.forename: Patrick
authors.initials: P
authors.lastname: Pauwels
authors.forename: Marc
authors.initials: M
authors.lastname: Peeters
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000737:chemistry / Q000473:pathology; D001005:Anus Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D001483:Base Sequence; D001530:Belgium; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D015331:Cohort Studies; D004252:DNA Mutational Analysis; D066246:ErbB Receptors / Q000032:analysis / Q000235:genetics*; D005091:Exons; D005260:Female; D005784:Gene Amplification; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D014067:Tonsillar Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018631:ras Proteins / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; C512478:EGFR protein, human; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins
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