Furthermore, the overexpression of several short-lived prosurvival and antiapoptotic proteins, such as c-Myc, Mcl-1, and survivin has been reported to contribute to the overproliferation and resistance to apoptosis phenotypes of cancer cells [19, 20], and these proteins are preferentially depleted by the inhibition of CDK9-mediated transcription elongation [13]. Here, MCL1 is linked to cancer.