BCR and B-cell chronic lymphocytic leukemia: Lastly, we assessed B-cell receptor (BCR)-responsiveness of CLL cells transduced with NOTCH1ΔPEST or EV. Anti-IgM induced a stronger calcium-flux in cells expressing NOTCH1ΔPEST compared to EV cells (Fig. 2g), supporting a recent study which demonstrated a collaboration between NOTCH- and BCR-signaling26.