Considering the genetic subtypes of pediatric B-ALL, the highest average numbers of subchromosomal aberrations (4.8–5.0 CNAs per patient) were observed in the BCR-ABL1-positive and iAMP21 subgroups, while the lowest values with 1.2–1.7 CNAs per patient were associated with hyperdiploidy and TCF3-PBX1 fusion (Table S5). The gene discussed is TCF3; the disease is precursor B-cell acute lymphoblastic leukemia.