Receptor tyrosine kinases (PTKs) play key roles in the pathogenesis Of numerous human diseases, including cancer. Therefore PTK inhibitors are currently Under intensive investigation as potential drug candidates. Herein, we report oil a ProteoChip-based screening of an epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitor, Erkitinibs, from phytochemical libraries. PLC-gamma-1 was used as a Substrate immobilized on a ProteoChip and incubated with an EGFR kinase to phosphorylate tyrosine residues of the substrate, followed by a fluorescence detection of the Substrate recognized by a phospho-specific monoclonal antibody. Erkitinibs inhibited HeLa cell proliferation in a dose-dependent manner. In conclusion, these data Suggest that Erkitinibs can be a specific inhibitor of an EGFR kinase and can be further developed as a potent anti-tumor agent. (C) 2009 Elsevier Inc. All rights reserved.