BCR and B-cell chronic lymphocytic leukemia: Treatment of CLL cells with ibrutinib, a drug that inhibits BTK and BCR signaling [27], inhibited the capacity of anti-μ to induce cortactin phosphorylation (Fig. 7a); but was unable to inhibit the capacity of Wnt5a to induce phosphorylation of cortactin (Y421) (Fig. 7b, c).