title: Changes in epidermal growth factor receptor expression during chemotherapy in non-small cell lung cancer.
abstract: BACKGROUND
  Antibodies targeting epidermal growth factor receptor (EGFR), such as cetuximab, may potentially improve outcome in non-small cell lung cancer (NSCLC) patients with high EGFR expression. The EGFR expression may be heterogeneously distributed within tumors, and small biopsies may thus not accurately reveal the EGFR expression. In addition, EGFR expression may also change during chemotherapy. The current study investigates the magnitude of these two issues.
  
  
  METHODS
  EGFR expression in diagnostic biopsies and resection specimen was compared in 53 NSCLC patients stage T1-4N0-1M0 treated with surgery without preceding chemotherapy (OP group), and 65 NSCLC patients stage T1-3N0-2M0 (NAC group) treated with preoperative carboplatin and paclitaxel in order to evaluate the discordance of EGFR expression between samples.
  
  
  RESULTS
  Discordance between tumors dichotomized according to EGFR expression (high: H-score ≥200; low: H-score <200) in diagnostic biopsies and immediate resection specimens was 25 % in the OP group and 33 % in the NAC group (p = 0.628). Five (9 %) of primary tumors in the OP group and 4 (13 %) in the NAC group had increased EGFR expression in the resection specimens as compared to the diagnostic biopsies (p = 0.583). A decrease in EGFR expression was observed in 6 (11 %) in the OP group and 7 (23 %) in the NAC group (p = 0.148).
  
  
  CONCLUSIONS
  EGFR expression in 25 % of diagnostic biopsies may potentially not be accurate compared to the prevailing pattern in the whole tumor based on the larger resection specimens. This may potentially be an obstacle for proper use of antibodies targeting the EGFR in NSCLC. EGFR expression does, however, not change significantly during paclitaxel and carboplatin and rebiopsies in order to decide on anti-EGFR antibody therapy following chemotherapy do not seem warranted.
authors: Department of Oncology, Rigshospitalet, 9 Blegdamsvej, 2100, Copenhagen, Denmark, jan.nyrop.jakobsen@rh.regionh.dk.
authors: Jan Nyrop
authors: JN
authors: Jakobsen
authors: Eric
authors: E
authors: Santoni-Rugiu
authors: Jens Benn
authors: JB
authors: Sørensen
mesh_terms: D000328:Adult; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000737:chemistry / Q000188:drug therapy* / Q000401:mortality; D066246:ErbB Receptors / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000235:genetics; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000737:chemistry / Q000188:drug therapy* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging
chemical_list: C512478:EGFR protein, human; D066246:ErbB Receptors