To circumvent apoptosis and sustain their own survival and propagation, cancer cells employ the multi-BH domain-containing anti-apoptotic BCL-2 family proteins, such as BCL-2, BCL-XL (the longer isoform of BCL2L1), and MCL1, to repress the pro-apoptotic BCL-2 family proteins by directly associating with the latter (Green, 2022). Here, MCL1 is linked to cancer.