KRAS and lung cancer: “Non-KRAS oncogene-driven lung cancer subtypes (e.g., ROS1, MET, BRAF, HER2, RET) is less well-studied, however, most of these other non-KRAS molecular subtypes (possibly apart from BRAF V600 mutation and MET gene alteration) are associated with a light-to-never smoking history [3,4,5].