A phase II study in well-differentiated and dedifferentiated liposarcoma patients showed a partial response in 1 of 29 evaluable patients, with a median PFS of 18 weeks.22 Even though the cyclin D1-CDK4/6-Rb axis has been thought to play a role in SyS, so far no studies have reported on the effects of inhibiting this axis in SyS. This evidence concerns the gene RB1 and liposarcoma.