Strikingly, decreased Heb (Heb/Tcf12+/-) compensates for the absence of pre-TCR signaling in Cd3e-/- mice and allowed SCLtgLMO1tg T-ALL to become fully penetrant, in addition to accelerating disease onset by 107 days (Figures 5A, B). The gene discussed is CD3E; the disease is acute lymphoblastic leukemia.