MAPK8 and B-cell chronic lymphocytic leukemia: The isoform of PKCβ mediating CARMA1 phosphorylation in B cells has not been clearly identified [37], so it is conceivable that low expression of PKCβI compared to PKCβII in CLL cells [148] limits the ability of the former to phosphorylate CARMA1 and initiate JNK signaling.