A subgroup of patients with non-small-cell lung cancer have specific mutations in the EGFR gene, which correlate with clinical responsiveness to the tyrosine kinase inhibitor gefitinib....Figure 2. Mutations in the EGFR Gene in Gefitinib-Responsive Tumors...Both had in-frame deletions in the kinase domain that were identical to those found in the patients with a response to gefitinib — namely, delL747–P753insS and delE746–A750 (Table 2).