Importantly, as protein expression analysis was performed selectively on CLL cells within the flow cytometric ‘high-FSC’ gate, i.e. a gate that contains, in the case of the CLL cell systems, only cells with intact ΔΨ dissipation and plasma membrane (as demonstrated in Bruno et al. [32]), we may deduce that metformin down-regulates Mcl-1 expression before mitochondrial perturbation and cell death. The gene discussed is MCL1; the disease is B-cell chronic lymphocytic leukemia.