CDKN1A and osteosarcoma: Our recent study suggests that CUL4B associates with DDB1, RBX1, and DCAF11 to form a unique CRL4BDCAF11 E3 complex in human osteosarcoma cells, and this E3 ligase can specifically target p21Cip1 for degradation, thereby regulating cell cycle progression (Chen et al., 2017).