title: Molecular determinants of cetuximab efficacy.
abstract: OBJECTIVE
  To investigate whether mRNA expression levels of cyclin D1 (CCND1), cyclooxygenase 2 (Cox-2), epidermal growth factor receptor (EGFR), interleukin 8 (IL-8), and vascular endothelial growth factor (VEGF), all members of the EGFR signaling pathway, are associated with clinical outcome in patients with EGFR-expressing metastatic colorectal cancer (CRC) treated with cetuximab.
  
  
  METHODS
  Thirty-nine patients with metastatic CRC, refractory to both irinotecan and oxaliplatin, were enrolled on IMCL-0144 and treated with single-agent cetuximab. The intratumoral mRNA levels of CCND1, Cox-2, EGFR, IL-8, and VEGF were assessed from paraffin-embedded tissue samples using laser-capture microdissection and quantitative real-time polymerase chain reaction.
  
  
  RESULTS
  There were 21 women and 18 men with a median age of 64 years (range, 35 to 83 years). Higher gene expression levels of VEGF were associated with resistance to cetuximab (P = .038; Kruskal-Wallis test). The combination of low gene expression levels of Cox-2, EGFR, and IL-8 was significantly associated with overall survival (13.5 v 2.3 months; P = .028; log-rank test). Both findings were independent of skin toxicity that was itself significantly correlated to survival. Patients with a lower mRNA amount of EGFR had a longer overall survival compared with patients that had a higher mRNA amount (7.3 v 2.2 months; P = .09; log-rank test). Patients with lower expression of Cox-2 had a significantly higher rate of grade 2 to 3 skin reactions under cetuximab treatment.
  
  
  CONCLUSIONS
  This pilot study suggests that gene expression levels of Cox-2, EGFR, IL-8, and VEGF in patients with metastatic CRC may be useful markers of clinical outcome in single-agent cetuximab treatment.
authors.affiliation: Division of Medical Oncology, Department of Preventive Medicine, University of Southern California/Norris Comprehensive Cancer Center, Keck School of Medicine, Los Angeles, CA 90033, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Vallböhmer
authors.forename: Wu
authors.initials: W
authors.lastname: Zhang
authors.forename: Michael
authors.initials: M
authors.lastname: Gordon
authors.forename: Dong Yun
authors.initials: DY
authors.lastname: Yang
authors.forename: Jim
authors.initials: J
authors.lastname: Yun
authors.forename: Oliver A
authors.initials: OA
authors.lastname: Press
authors.forename: Katrin E
authors.initials: KE
authors.lastname: Rhodes
authors.forename: Andy E
authors.initials: AE
authors.lastname: Sherrod
authors.forename: Syma
authors.initials: S
authors.lastname: Iqbal
authors.forename: Kathleen D
authors.initials: KD
authors.lastname: Danenberg
authors.forename: Susan
authors.initials: S
authors.lastname: Groshen
authors.forename: Heinz-Josef
authors.initials: HJ
authors.lastname: Lenz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000068818:Cetuximab; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D051546:Cyclooxygenase 2; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D009367:Neoplasm Staging; D010865:Pilot Projects; D011336:Probability; D011379:Prognosis; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D016896:Treatment Outcome; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D005819:Genetic Markers; D016209:Interleukin-8; D008565:Membrane Proteins; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D066246:ErbB Receptors; D000068818:Cetuximab