A gene that makes a protein called ROS1, which is involved in sending signals in cells and in cell growth. Mutated (changed) forms of the ROS1 gene have been found in some types of cancer, including non-small cell lung cancer (NSCLC), a type of brain cancer called glioblastoma multiforme, and cancers of the bile duct, ovary, stomach, colon, and rectum. ROS1 is a type of receptor tyrosine kinase.