CD4 and acute lymphoblastic leukemia: Sca1‐Lmo2 mice had a shorter lifespan than their wild‐type (WT) littermates due to a highly disseminated form of T‐ALL, consisting of a clonally immature CD8 or CD4 single‐positive/DP‐like population (Fig 2A–C; Appendix Fig S5A–E), as reported for human T‐ALL (Van Vlierberghe et al, 2006) and Rosa26‐Lmo2 + Sca1‐Cre mice (Fig 1).