ROS1 and digestive system neoplasm: Examples include EGFR, ALK, ROS1 and RET alterations in non-small cell lung cancer, rendering tumors susceptible to tyrosine kinase inhibitors (79), or high microsatellite instability/deficient mismatch repair (MSI-H/dMMR) in gastrointestinal tumors, which is associated with response to PD1 inhibition (80).