RT Journal Article SR Electronic T1 Erlotinib Antitumor Activity in Non-small Cell Lung Cancer Models is Independent of HER1 and HER2 Overexpression JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 3505 OP 3512 VO 26 IS 5A A1 T. FRIESS A1 W. SCHEUER A1 M. HASMANN YR 2006 UL http://ar.iiarjournals.org/content/26/5A/3505.abstract AB Background: The human epidermal growth factor receptors HER1/EGFR and HER2 offer potential targets for treating non-small cell lung cancer (NSCLC). The antitumor efficacy of erlotinib (Tarceva, F. Hoffmann-La Roche, Ltd., Basel, Switzerland), a HER1/EGFR tyrosine-kinase inhibitor, was investigated in relation to HER1/EGFR and HER2 expression in five NSCLC xenograft models. Materials and Methods: Tumor-bearing mice were randomized to daily oral erlotinib, 50 mg/kg, or vehicle (controls) for 20-50 days. The antitumor efficacy of erlotinib was measured through tumor volume, serum tumor markers and tumor biomarkers. Tumor HER1/EGFR and HER2 expression were analyzed immunohistochemically. Results: Erlotinib reduced tumor volume in three NSCLC models. It also reduced serum tumor marker levels and the extent of inhibition correlated with tumor growth inhibition. HER1/EGFR and HER2 expression differed between the five tumor models, suggesting that expression level does not predict response to treatment. Conclusion: Erlotinib showed differing antitumor activity in five NSCLC models, suggesting that its antitumor effect is independent of HER1/EGFR and HER2 overexpression. Copyright© 2006 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved