The deregulation of PKC activity/expression in CLL cells was recognized in an early study demonstrating that total PKC activity in CLL was lower than that observed in acute myeloid leukaemia (AML) and acute lymphoblastic leukaemia (ALL) in the particulate and cytosolic fractions; however, a high level of PKCβ expression was associated with CLL in comparison with PKCα and PKCγ [25]. This evidence concerns the gene PRKCA and acute myeloid leukemia.