We have previously shown that Mcl-1 protein levels rapidly is decreased in cancer cells when targeted with several of our Pseudomonas Exotoxin A based immunotoxins [7], [11], of which one (the MOC31PE targeting the EpCAM antigen) is currently in clinical trial phase I/II (www.clinicaltrials.gov, assessed July 20, 2011). The gene discussed is MCL1; the disease is cancer.