According to a study analyzing cell-free circulating tumor DNA (cftDNA) based on droplet digital polymerase chain reaction (DDPCR) platform, KRAS mutation at codon 12 was found in 16 out of 33 (48.5%) plasma samples from patients after EGFR-TKIs progression and 13 (39.4%) had the commutation of KRAS and T790M [2]. Here, EGFR is linked to neoplasm.