TCL1B and cancer: On the basis of the structural functional analysis of the TCL1-Akt protein complex, we have previously identified and characterized a TCL1 structure-based peptide, named ‘Akt-in' (Akt inhibitor, NH2-AVTDHPDRLWAWEKF-COOH encompassing the βA strand of TCL1), interacted with Akt and specifically inhibited its kinase activity and proliferation of cancer cells.11, 33 The amino-acid sequences of the protooncogene TCL1 and TCL1b share a relatively high sequence homology with a possible common three-dimensional structure.