CD74 and non-small cell lung carcinoma: The proto‐oncogene, ROS1, which is mutated in multiple solid tumors and results in the dysfunction of a tyrosine kinase‐mediated signaling pathway, was identified specifically in non‐small‐cell lung cancer (NSCLC) patients in 2007 in cases where ROS1 rearrangements occurred between the fusion partner, solute carrier family 34 member 2 gene (SLC34A2) and CD74 molecule gene (CD74) [1].