p57Kip2 (or CDKN1C) is a potent tight-binding inhibitor of several G1 cyclin complexes, and is a negative regulator of cell proliferation. The gene encoding human p57Kip 2 is located on chromosome 11p 15.5, a region implicated in both sporadic cancers, Wilm's tumor, and Beckwith-Wiedemann syndrome (BWS), a cancer syndrome, making it a tumor supressor candidate. BWS is characterized by numerous growth abnormalities and an increased risk of childhood tumors. Several types of childhood tumors including Wilms' tumor, adrenocortical carcinoma and rhabdomyosarcoma display a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting plays an important part. This region also contains two other imprinted genes, insulin-like growth factor II (IGF-II) and H19, both of which seem to be implicated in adrenal neoplasms.