CDK4 and liposarcoma: The dedifferentiated liposarcomas are characterized by mouse double minute 2 (MDM2) and cyclin-dependent kinase 4 (CDK4) amplifications, and the CDK4 inhibitor, abemaciclib, is currently under investigation; an encouraging 12-week PFS of 76% in a phase II nonrandomized trial has been reported [27,190] (Table 5).