TCF1 protein was expressed equivalently in E2a-/- and DKO leukemias suggesting that LEF1 does not promote leukemogenesis by repressing Tcf7. Given that E2a-/- leukemias are not ETP-like, we do not think that the major function of LEF1 is simply antagonism of TCF1. This evidence concerns the gene TCF7 and leukemia.