Thus, CDK2 might be only a CUL4B-associated protein, and its down-regulation in osteosarcoma cells expressing lower CUL4B, DDB1 or DCAF11 might not be regulated by DCAF11 but might rather be regulated by p21 induction, as p21 is an inhibitor of CDK2. Here, CDKN1A is linked to osteosarcoma.