KIT and T-cell leukemia: Representative flow plots demonstrate: a CD3 + CD4 + T-cell leukemia in a Chek2p.I161T/p.I161T mouse (Supplemental Fig. 16A), transplantable to a CD45.1 recipient (Supplemental Fig. 16B), and clonality demonstrated by the presence of a dominant clone by TCR sequencing (Supplemental Fig. 17A); a CD34 + CD11b + CD117+ proliferation in a Chek2p.I161T/p.I161T mouse (Supplemental Fig. 16C); and a B-cell lymphoproliferative disease (LPD) in a Chek2p.I161T/wt mouse (Supplemental Fig. 16D), with a dominant clone identified by BCR sequencing (Supplemental Fig. 17B).