ROS1 and adenocarcinoma: Current updated international guidelines recommend that NSCLC patients with verified or probable adenocarcinoma histology or those with mixed histology including an adenocarcinoma component, younger NSCLC patients, and patients without a history of smoking, should be tested for EGFR-mutations, ALK-fusions and ROS1-fusions to identify candidates to first-line therapy with specific TKIs [49,50].