ROS1 and small cell lung carcinoma: Remarkably, tumors harboring LUAD driver mutations associated with a low/never-smoking profile (EGFR mutations and fusions of ALK, RET or ROS1) are enriched in low/never-smoking patients diagnosed with LUAS, LUSC, combined histology SCLC, LCNEC or SCLC43,44 (Fig. 2c, d), even if these tumor types are strongly associated with a heavy smoking profile.