Because the HR pathway is a key component in the G2/M checkpoint, we examined if a RAD51B expression signature of genes co-expressed with RAD51B across single KBM7 cells (“Methods”, Supplementary Table 4) is associated with the elevated G2/M checkpoint response we observed in near-haploid B-ALL cells. Here, RAD51B is linked to precursor B-cell acute lymphoblastic leukemia.