BCR and B-cell chronic lymphocytic leukemia: To determine if R-RAS2 is also mediating BCR signaling in leukemic cells from Rosa26-RRAS2xmb1-Cre mice, we first analyzed those cells by phosflow cytometry in parallel to B cells from WT controls and to B cells from Rras2(Q72L)fl/fl xmb1-Cre mice, which do not develop CLL (Fig. S6a-f).