LTK and hereditary pheochromocytoma-paraganglioma: Roll and Reuther evaluated the ALK activating mutations in LTK, using a benign tumor model (pheochromocytoma—adrenal gland benign tumor) in mice.219 This study identified specific ALK mutations like F1147L and R1275Q, and the corresponding LTK mutations F568L and R669Q.