MCL-1 is an anti-apoptotic member of the BCL-2 family of PPIs that collectively determine cellular response to pro and anti-apoptotic stimuli.59 The canonical BCL-2 interaction involves docking of the BH3 domain from a family member in a helical conformation to a cleft on a multi-BH-domain partner.60 MCL-1 is a particularly attractive target because of its role in multiple cancers and its immunity to inhibition by other BCL-2 family inhibitors.61 As a result, chemical probes have been developed to validate it as a target for preclinical studies.62 Here, BCL2 is linked to cancer.