TBL1XR1 and juvenile myelomonocytic leukemia: In a genomic study of patients with juvenile myelomonocytic leukemia (JMML), 16 patients had no RAS variants, and in three of these that were 56 months of age or older, the researchers identified ALK/ROS1 tyrosine kinase fusions (DCTN1-ALK, RANBP2-ALK, and TBL1XR1-ROS1).