CDKN1B and neoplasm: In support of this hypothesis, Skp2 has been shown to recognize Cyclin-dependent kinase (Cdk) inhibitors and tumor suppressive proteins such as p27 Kip1 (Cyclin-dependent kinase inhibitor 1B), p57 Kip2 (Cyclin-dependent kinase inhibitor 1C), p130 (130 kDa retinoblastoma-associated protein) and Tob1 (transducer of ERBB-2 1), but not c-Myc [13]–[16].