MAPK3 and B-cell chronic lymphocytic leukemia: Blocking of CD38 downstream results in decreased p-Syk, p-BTK, p-ERK1/2 and p-AKT: these two latter are even more reduced in CD38- patients, and simultaneous inhibition of CD38 and BTK in CLL cell from CD38- patients leads to a significant downregulation of only p-BTK, p-PLCγ2 and p-ERK1/2 (26).