- Pre-B ALL patients in CR1 with high-risk features such as adverse cytogenetics including t(9;22), t(4;11) or other MLL rearrangements, t(8;14), complex karyotype (≥5 chromosomal abnormalities), hypodiploidy (<44 chromosomes), low hypodiploidy (30-39 chromosomes)/near triploidy (60-68 chromosomes), high WBC count at presentation (≥30,000), lack of achievement of complete remission after standard induction chemotherapy (but achieved CR1 following salvage or consolidation), or persistence of detectable disease after induction and consolidation (intensification) or pre-transplant as documented on any of routine clinical tests (morphology, flow cytometry, cytogenetics or molecular studies) OR all Pre-B ALL patients in second and higher CR