PT - JOURNAL ARTICLE AU - T. FRIESS AU - W. SCHEUER AU - M. HASMANN TI - Erlotinib Antitumor Activity in Non-small Cell Lung Cancer Models is Independent of HER1 and HER2 Overexpression DP - 2006 Sep 01 TA - Anticancer Research PG - 3505--3512 VI - 26 IP - 5A 4099 - http://ar.iiarjournals.org/content/26/5A/3505.short 4100 - http://ar.iiarjournals.org/content/26/5A/3505.full SO - Anticancer Res2006 Sep 01; 26 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