ROS1 and carcinoma: Numerous studies have examined the involvement of classic lung cancer oncogenic pathways in the development of pulmonary lymphoepithelioma-like carcinoma, including EGFR [4, 6, 7, 15, 23, 24], KRAS, BRAF, ALK, and ROS1 [23] and discovered that these pathways are not major oncogenic drivers of pulmonary lymphoepithelioma-like carcinoma.