The increased levels of TERRA found in MLL-r ALL contrast with their reduction during the progression of telomerase-positive astrocytoma or squamous cell, hepatocellular, and endometrial carcinoma [51,52,53,54], suggesting an advantage conferred by high levels of TERRA to this poor-prognosis leukemia subtype. This evidence concerns the gene KMT2A and astrocytoma (excluding glioblastoma).