TAL1 (T cell acute lymphocytic leukaemia 1), also known as SCL (stem cell leukaemia), is a critical haematopoietic regulator that plays a key role in both embryonic and adult HSC specification and its rearrangement is associated with several human leukaemias (Lécuyer & Hoang, 2004). Here, TAL1 is linked to leukemia.