I hope it's an open question, since I can not find the statements.
The monitoring mechanisms are in addition to the regulation of the succession of the four phases of the cycle by the Cdk. They allow the monitoring of fundamental aspects such as the state of the DNA molecules before, during and after their replication (DDCP = DNA Damage Checkpoint), the total completion of the replication before the entry into mitosis (RCP = Replication Checkpoint ) and the correct positioning of all chromosomes on the metaphase plate before sister chromatid separation (MPC = Mitotic Checkpoint).
Disruption of the cell cycle leads either to cell death because the cell can no longer continue its cycle, in the worst case to anarchic proliferation. The major interest of the study of the regulation of the cell cycle and its points of surveillance lies in the fact that these processes are often unregulated in cancers. Knowing the regulation of the cell cycle is therefore fundamental for oncology and can be used to develop new therapeutic approaches.