MAPK3 and B-cell chronic lymphocytic leukemia: To verify whether CLL samples at progression were indeed still responsive to BCR stimulation, we performed in-vitro stimulations with anti-IgM, CD40 ligand (CD40L) or CpG, in presence or not of ibrutinib and measured the phosphorylation of BTK and ERK1/2 proteins by phosphoflow [7].