In NSCLC particularly, oncogenic gene rearrangement frequently leads to expression of oncogenic fusion proteins by the oncogene formation by a 5′ partner creating an in‐frame gene fusion with a 3′ proto‐oncogene.57, 58, 59 Prominent examples are the Echinoderm microtubule‐associated protein‐like 4 (EML4)‐ALK fusion gene, ROS‐1‐ and RET‐fusions. The gene discussed is ROS1; the disease is non-small cell lung carcinoma.