title: Gene expression profiling of archival tongue squamous cell carcinomas provides sub-classification based on DNA repair genes.
abstract: A subgroup of patients with squamous cell carcinoma of the head and neck (SCCHN) comprise young persons under the age of 40, who have not been heavily exposed to the classical risk factors, smoking and alcohol. The number of SCCHN in young adults, particularly tongue tumours, is increasing in several parts of the world. Here we employed a novel gene expression array methodology specifically developed for analysis of degraded RNA and investigated the expression of 502 cancer-related genes in archival paraffin-embedded SCCHN of the tongue from young (< or =40) and elderly patients (> or =50). Genes detected as de-regulated in tumours compared to non-malignant controls were in concordance with results from earlier studies of fresh frozen material. No genes were detected as significantly differentially expressed between young and old patients suggesting that the overall pathobiology of SCCHN is similar in young and old. Unsupervised clustering divided tumours into three groups, irrespective of age, where several differentially expressed DNA repair genes were a prominent separation factor. High levels of DNA repair genes associated with impaired therapeutic response to radiation, suggesting that DNA repair genes play a role in clinical outcome after radiotherapy.
authors.affiliation: Department of Medical Biosciences/Pathology, Umeå University, SE-901 85 Umeå, Sweden. matilda.rentoft@medbio.umu.se
authors.forename: Matilda
authors.initials: M
authors.lastname: Rentoft
authors.forename: Göran
authors.initials: G
authors.lastname: Laurell
authors.forename: Philip John
authors.initials: PJ
authors.lastname: Coates
authors.forename: Björn
authors.initials: B
authors.lastname: Sjöström
authors.forename: Karin
authors.initials: K
authors.lastname: Nylander
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000145:classification / Q000235:genetics* / Q000473:pathology; D004260:DNA Repair / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014062:Tongue Neoplasms / Q000145:classification / Q000235:genetics* / Q000473:pathology
chemical_list: D012333:RNA, Messenger