KRAS and neoplasm: Among the nine patients with BPM, driver mutations of primary tumours were determined by NGS, including EGFR mutations (5, 55.6%), which include 19del (4, 44.4%), L858R+A871E + MET (1, 11.1%), ALK (1, 11.1%), ROS1 (1, 11.1%), KRAS (1, 11.1%), and unknown (1, 11.1%).