The kinase activity of CDK12 was required for the proliferation of NUP98::KDM5A AML cells, as exogenous expression of wild-type CDK12, but not a kinase-dead mutant of CDK12 (CDK12D873N)57 restored proliferation in cells harboring Cdk12-targeting shRNAs (Fig. 6D). Here, CDK12 is linked to acute myeloid leukemia.