A number of high-risk factors, such as infant age, T-cell lineage, hyperleukocytosis, and specific chromosomal aberrations in B-ALL, like KMT2A gene rearrangements, t(9;22)[BCR-ABL1] and t(1;19)[TCF3-PBX1] are linked to CNS involvement [33]. This evidence concerns the gene TCF3 and acute lymphoblastic leukemia.