Anticancer agents such as the pan-cyclin dependent kinase (CDK) inhibitors flavopiridol and seliciclib elicit their antitumor activity by inhibiting RNA polymerase II [12]–[14], leading to suppression of the expression of short-lived antiapoptotic proteins such as Mcl-1, XIAP, Bcl-XL, and survivin [15]–[17], suggesting that RNA polymerase II may serve as a therapeutic target for cancers. Here, MCL1 is linked to cancer.