title: A novel serum protein signature associated with resistance to epidermal growth factor receptor tyrosine kinase inhibitors in head and neck squamous cell carcinoma.
abstract: BACKGROUND
  Acquired resistance to tyrosine kinase inhibitors (TKIs) is becoming a major challenge in the treatment of many cancers. Epidermal growth factor receptor (EGFR) is overexpressed in squamous carcinomas, notably those of the head and neck (HNSCC), and can be targeted with several TKIs. We aimed to identify soluble proteins suitable for development as markers of EGFR TKI resistance in cancer patients to aid in early and minimally invasive assessment of therapeutic responses.
  
  
  METHODS
  Resistant HNSCC cell lines were generated by exposure to an EGFR TKI, gefitinib, in vitro. Cell lines were characterised for their biological behaviour in vitro (using growth inhibition assays, flow cytometry, western blots, antibody arrays and/or immunoassays) and in vivo (using subcutaneous tumour xenografts). Sera from EGFR-treated and -untreated HNSCC patients were analysed by immunoassay.
  
  
  RESULTS
  Two independent sublines of CAL 27 and a PJ34 subline with acquired resistance to EGFR TKIs (gefitinib, erlotinib and afatinib) were developed. Resistant cells grew as highly aggressive xenografts leading to reduced host survival rates compared with EGFR-TKI sensitive cells. This suggested a link between resistance in vitro and poor prognosis in vivo. A significant upregulation of proteins linked to tumour angiogenesis and invasion was identified in resistant cells. This 'resistance-associated protein signature' (RAPS) was detected in the sera of a small cohort of HNSCC patients and was associated with reduced survival.
  
  
  CONCLUSIONS
  We have identified a protein signature associated with EGFR-TKI resistance that may also be linked to poor prognosis and warrants further investigation as a potential clinical biomarker.
authors.affiliation: Tumour Biology & Metastasis Team, Division of Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK.
authors.forename: Carol
authors.initials: C
authors.lastname: Box
authors.affiliation: Pathology and Oncology Laboratory, IdiPAZ, Hospital La Paz, Madrid 28046, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Mendiola
authors.affiliation: Tumour Biology & Metastasis Team, Division of Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK; Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK.
authors.forename: Sharon
authors.initials: S
authors.lastname: Gowan
authors.affiliation: Tumour Biology & Metastasis Team, Division of Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK; Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Box
authors.affiliation: Tumour Biology & Metastasis Team, Division of Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK; Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK.
authors.forename: Melanie
authors.initials: M
authors.lastname: Valenti
authors.affiliation: Tumour Biology & Metastasis Team, Division of Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK; Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK.
authors.forename: Alexis De Haven
authors.initials: Ade H
authors.lastname: Brandon
authors.affiliation: Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK.
authors.forename: Bissan
authors.initials: B
authors.lastname: Al-Lazikani
authors.affiliation: Tumour Biology & Metastasis Team, Division of Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK.
authors.forename: Susanne J
authors.initials: SJ
authors.lastname: Rogers
authors.affiliation: The Head and Neck Unit, Royal Marsden Hospital, Fulham Road, London SW3 6JJ, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Wilkins
authors.affiliation: The Head and Neck Unit, Royal Marsden Hospital, Fulham Road, London SW3 6JJ, UK; Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Harrington
authors.affiliation: Tumour Biology & Metastasis Team, Division of Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK; Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK. Electronic address: sue.eccles@icr.ac.uk.
authors.forename: Suzanne A
authors.initials: SA
authors.lastname: Eccles
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002294:Carcinoma, Squamous Cell / Q000097:blood* / Q000188:drug therapy* / Q000201:enzymology; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000008:administration & dosage; D019295:Computational Biology; D018450:Disease Progression; D019008:Drug Resistance, Neoplasm; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D000077156:Gefitinib; D006258:Head and Neck Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000201:enzymology; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000097:blood*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011799:Quinazolines / Q000008:administration & dosage; D000077195:Squamous Cell Carcinoma of Head and Neck; D016019:Survival Analysis; D023041:Xenograft Model Antitumor Assays
chemical_list: D009363:Neoplasm Proteins; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D066246:ErbB Receptors; D002945:Cisplatin; D000077156:Gefitinib; D005472:Fluorouracil