We first assessed the activity of afatinib in 11 human EGFR mutant NSCLC cell lines by using the MTT (tetrazolium-based semiautomated colorimetric 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cell proliferation assay (Figure 1 and Table 1). The gene discussed is EGFR; the disease is non-small cell lung carcinoma.