Studying whether the T‐ALL cases are Lmo2‐Tomato‐positive or Lmo2‐Tomato‐negative has allowed identifying whether the Lmo2 expression is needed for the survival of T‐ALL cells (Tomato+) or it serves as an earlier reprogramming event in leukemogenesis (Tomato−). Here, LMO2 is linked to acute lymphoblastic leukemia.