title: Microsatellite instability and loss of heterozygosity in squamous cell carcinoma of the head and neck.
abstract: BACKGROUND
  Microsatellite instability (MSI) in head and neck squamous cell carcinoma (HNSCC) has been reported with a wide range of frequencies. The aim of our study was to disclose the frequency and basis of MSI in HNSCC and to correlate MSI and findings on loss of heterozygosity (LOH) with the clinical data.
  
  
  METHODS
  We analyzed MSI and LOH in 91 tumors. All tumors presenting instability were analyzed for the expression of mismatch repair genes (MMR) proteins.
  
  
  RESULTS
  Low-level microsatellite instability (MSI-L) was seen in 7.7% of the HNSCC. None of the MSI-L tumors had aberrant MMR protein expression. LOH rates up to 57% were identified for different regions on chromosome 3p. For the marker D10S197, we found a significant correlation between LOH and tumor stage IV.
  
  
  CONCLUSIONS
  Our results indicate that MMR gene inactivation is rare among primary HNSCC. In contrast, the MSI-L phenotype plays a role in a small subset of tumors. LOH on chromosome arm 3p and 10p12 seems to be involved in tumorigenesis and progression HNSCC, respectively.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospital Carl Gustav Carus, Technical University Dresden, Fetscherstr. 74, 01307 Dresden, Germany. susanne.koy@web.de
authors.forename: Susanne
authors.initials: S
authors.lastname: Koy
authors.forename: Jens
authors.initials: J
authors.lastname: Plaschke
authors.forename: Hella
authors.initials: H
authors.lastname: Luksch
authors.forename: Katrin
authors.initials: K
authors.lastname: Friedrich
authors.forename: Eberhard
authors.initials: E
authors.lastname: Kuhlisch
authors.forename: Uwe
authors.initials: U
authors.lastname: Eckelt
authors.forename: Ramon
authors.initials: R
authors.lastname: Martinez
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D053843:DNA Mismatch Repair; D005091:Exons; D005260:Female; D005819:Genetic Markers; D006258:Head and Neck Neoplasms / Q000235:genetics* / Q000473:pathology; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000235:genetics; D020539:Sequence Analysis, Protein
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D005819:Genetic Markers; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D000070957:MutL Protein Homolog 1