JAK2 and T-cell leukemia: We found that Tcra−/−;Relb−/− recipient mice reconstituted with TEL-JAK2;Tcra−/− bone marrow cells (TEL-JAK2;Tcra−/−→Tcra−/−;Relb−/−) developed T-cell leukemia with delayed onset, as compared to the reconstituted Tcra−/−;Relb+/+ littermates (TEL-JAK2;Tcra−/−→Tcra−/−;Relb+/+) (median survival of 46 and 23 weeks, respectively; P<0.01; Figure 6B).