FIGURE 5 Summary of EGFR mutations and their effects on sensitivity and resistance towards inhibition by EGFR small molecule inhibitors
From the following article:
Gefitinib response of erlotinib-refractory lung cancer involving meninges—role of EGFR mutation
Nicholas W Choong, Sascha Dietrich, Tanguy Y Seiwert, Maria S Tretiakova, Vidya Nallasura, Gareth C Davies, Stanley Lipkowitz, Aliya N Husain, Ravi Salgia and Patrick C Ma
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Figure 5. Summary of EGFR mutations and their effects on sensitivity and resistance towards inhibition by EGFR small molecule inhibitors
The known somatic missense mutations of EGFR and their effects on sensitivity and resistance towards erlotinib or gefitinib inhibition are shown schematically. L858R sensitizes the receptor to both inhibitors to a similar extent, and more than the wild-type receptor. T790M is the recently reported resistant mutation against both EGFR inhibitors. E884K gives the receptor a sensitizing effect towards gefitinib, while rendering it more resistant to erlotinib. The double mutation L858R + E884K also sensitizes the receptor to gefitinib inhibition, with a synergistic effect when compared with E884K alone, and confers resistance to erlotinib. Of note, the most sensitizing mutation towards gefitinib inhibition is EGFRL858R + E884K, identified in this patient. Hence, the effects of EGFR mutations on TKIs can be divided into: Class I, sensitizing responses; Class II, resistant responses; and Class III, differential responses. S, sensitive; R, resistant.
