JAK2 and T-cell leukemia: Both groups of bone marrow chimeric mice developed T-cell leukemia with similar onset (median survival of 18 and 17 weeks for TEL-JAK2;Tcra−/−;Relb+/−→WT and TEL-JAK2;Tcra−/−;Relb−/−→WT mice, respectively) (Figure 5B).