As compared with the control, the Ki-67 index in the tumor tissues was significantly decreased after the gefitinib treatment (Ki-67 index: 4.6 ± 2.4% for 100 mg/kg; 6.2 ± 1.8% for 200 mg/kg; 10.4 ± 5.7% for control group; p < 0.01 for both treated groups vs. control group). This evidence concerns the gene MKI67 and neoplasm.