EGFR and lung cancer: The correlation between treatment response and low abundances of EGFR mutations was preliminary demonstrated in 2011; it was identified by direct DNA sequencing and ARMS approaches that lung cancer patients with low abundances (~1%) of EGFR mutations had a clearly longer median progression-free survival, higher objective response rate (ORR) and overall survival (OS) rate as compared with those of patient with wild-type EGFR, and the difference between patients with high and low abundances of EGFR mutations was not found to be significant regarding ORR and OS (16).