ROS1 and cancer: To elucidate mechanisms underlying acquired resistance to crizotinib in cancer cells harbouring the ROS1 fusion gene, we previously performed N-ethyl-N-nitrosourea (ENU) mutagenesis screening of Ba/F3 cells expressing CD74-ROS1 and identified multiple crizotinib resistant mutations including G2032R solvent front mutation and demonstrated that cabozantinib effectively inhibited the G2032R ROS1 mutation20.