MCL1 and osteosarcoma: Preclinical studies in several cancer types, including osteosarcoma, synovial sarcoma, endometrial cancer, and leukemia, have focused on targeting CDK9 due to its role in controlling transcription of super-enhancer driven oncogenes such as MYC and anti-apoptotic proteins such as myeloid-cell leukemia 1 (MCL-1), which maintain cancer cell survival [22,23,24,25,26].