ABL1 and acute lymphoblastic leukemia: According to the NCCN Guidelines Version 1.2015 Acute Lymphoblastic Leukemia, high risk is generally defined as having any of the following poor-risk cytogenetic factors: hypodiploidy (<44 chromosomes); t(v;11q23) or MLL rearrangements; t(9;22) or BCR-ABL gene mutations; or complex karyotype (≥5 chromosomal abnormalities), while the absence of all poor-risk factors is considered standard risk.