EGFR and neoplasm: Jackman et al. (17) defined secondary resistance with the following criteria: previous treatment with a single-agent EGFR-TKI; either both of the following: a tumor that harbors an EGFR mutation known to be associated with drug sensitivity or objective clinical benefit from treatment with an EGFR-TKI; systemic progression of disease (RECIST or WHO) while on continuous treatment with gefitinib or erlotinib within the last 30 days; and no intervening systemic therapy between cessation of EGFR-TKI and initiation of new therapy (Table 2).