The protein encoded by this gene is a tight-binding, strong inhibitor of several G1 cyclin/Cdk complexes and a negative regulator of cell proliferation. Mutations in this gene are implicated in sporadic cancers and Beckwith-Wiedemann syndorome, suggesting that this gene is a tumor suppressor candidate. Three transcript variants encoding two different isoforms have been found for this gene.Tissue specificity: Expressed in the heart, brain, lung, skeletal muscle, kidney, pancreas and testis. High levels are seen in the placenta while low levels are seen in the liver.