Indeed, a recent study provided preliminary evidence that the ARTD1/2 inhibitor olaparib selectively targets ATM mutant (DNA-DSB repair deficient) but not wild-type (DNA-DSB repair proficient) B-lymphoid cells, including proliferating primary CLL cells in vitro and in vivo [489]. The gene discussed is PARP1; the disease is B-cell chronic lymphocytic leukemia.