To confirm these findings, we then treated our two independent BRCA2 haploinsufficient clones with either VE-821 or the structurally distinct ATR inhibitor AZD6738 [54], and found that ATR inhibition exhibits sustained differential toxicity to BRCA2 haploinsufficient Jurkat T-ALL cells (Fig 5B and 5C). Here, BRCA2 is linked to acute lymphoblastic leukemia.