To determine the effects of gefitinib on EGFR expression and receptor phosphorylation, four tumor cells (SCC-1, 22B, A549, and HT-29) were pretreated with gefitinib at 0.00, 0.05, 0.1, 0.5, or 1 μM in the presence of hEGF (10 μM), followed by western blot analysis. This evidence concerns the gene EGFR and neoplasm.