PARP1 and acute myeloid leukemia: Given the low frequency of PARP1 mutations in hematopoietic and lymphoid blood cancers (41 of 5,212 currently tested44) together with the ability of both PARP-1 interference and PARP-1 overexpression to decrease drug sensitivity (Figures 2H and 2I), we hypothesized that median levels of PARP1 expression can be associated with improved M4/M5 AML survival.