Table 2. The prevalence of important resistance mechanisms of second-generation EGFR-TKIs reported in recent studies.

Agents	Study	Sample	Methods	Number	T790M mut % (n)	C-Met amp % (n)	Unkown % (n)	Multiple % (n)	References
Afatinib	Campo et al.	Tumor samples	SNaPshot FISH ICH	11	36.4% (4)	9.1% (1)	54.5% (6)	-	[18]
	Wu et al.	Tumor samples	Sequencing	42	47.6% (20)	NA	52,4% (22)	-	[19]

“-”represents there were no patients in the cohort; NA: not available; amp: amplification; FISH: Fluorescence in situ hybridization; ICH: Immunohistochemistry; SNaPshot: A multiplexed allele-specific PCR-based platform.