ROS1 and cancer: ROS1 is a proto-oncogene located on the long arm of chromosome 6, encoding a receptor tyrosine kinase involved in the regulation of cancer cell growth and differentiation.[13] Fusion products of ROS1 have been observed in a variety of types of cancer, including lung cancer, glioma, hepatic angiosarcoma, gastric adenocarcinoma, and ovarian cancer.[14] This is the first report of a TJP1-ROS1 fusion identified using NGS.