The Jun transcription factor positively regulates the expression of cyclin D1, a CDK4/6 cyclin partner, and amplification of JUN in DDLS is associated with a more aggressive phenotype5, calling for investigation of whether CDK4 and JUN co-amplification drives progression to DDLS or modulates response to CDK4 inhibition. This evidence concerns the gene JUN and dedifferentiated liposarcoma.