Another BCR pathway protein overexpressed in CLL cells, Lyn, is similar to PKCβ in promoting the expansion of the malignant clone through its role within microenvironmental cells; however, it differs because Lyn deficiency does not affect the rate of malignant cell transformation in the Eμ-Tcl1 murine model of CLL [29]. Here, BCR is linked to B-cell chronic lymphocytic leukemia.