Daily oral administration of gefitinib (150 mg kg−1, five times a week) significantly suppressed tumour growth of HER2-overexpressing cells (GLM-1, GLM-4 and NCI-N87) in a dose-dependent manner, whereas no significant inhibition of tumour growth was observed with HER2 low-expressing cell lines (MKN-28) (Figure 2D). The gene discussed is ERBB2; the disease is neoplasm.