Although rearrangements and mutations of p27/kip1 are extremely rare events, p27 levels are reduced and associated with a poor prognosis in many human carcinomas.     ///    Proteasome-dependent degradation of p27/kip1 in gliomas..     ///    " p27/kip1 regulates the G1-S transition of the cell cycle by inhibiting cyclin D-CDK4, cyclin E-CDK2, and cyclin A-CDK2. "