The clinical development of short hairpin RNA mimicking endogenous microinterfering RNA (miR) appears to be even more difficult to apply [32] whereas the loss of miR-15a1 and miR-16 (targeting notably Bcl-2 and Mcl-1) in CLL was the first event of this type to be discovered [33]. The gene discussed is MCL1; the disease is B-cell chronic lymphocytic leukemia.