The metastatic sites of the ROS1-rearranged cases also expressed the ROS1 protein, which suggested that the histomorphology of metastatic tumors could be evaluated for identifying patients with ROS1 rearrangement, and screening for ROS1 could also be conducted in metastatic tumors on the condition of primary tumors were unavailable. The gene discussed is ROS1; the disease is metastatic neoplasm.