Is involvement of Tcl1 in Akt activation important in the pathogenesis of CLL? The fact that transgenic mice overexpressing activated Akt in T-cells develop T-cell leukemias [39] provides an important evidence that Akt contributes to lymphomagenesis in T-cells initiated by TCL1 activation (Figure 2). On the other hand, transgenic mice expressing activated Akt in B-cells do not develop lymphoid malignancies (YP and CMC, unpublished results), and conditional Pten knockout in mouse B-cells expressing constitutively active Akt did not cause B-cell transformation [40]. Thus, it is likely that Tcl1 mediated CLL pathogenesis is caused by mechanism(s) other than Akt activation.
