SR indicates National Cancer Institute-classified standard-risk precursor B-cell ALL (age range, 1-9 years and peripheral-blood leukocyte count at diagnosis <50 000/μL); HR, high-risk (age range, 10-15 years and leukocyte count ≥50 000/μL); adolescent, age 16-20 years; and young adult, age 21-39 years. (Data are taken from Roberts et al.²⁰ )