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Cell cycle and cancer.

PURPOSE
To evaluate the link between cell cycle dysfunctions and tumor formation.


DESIGN
A review of the cell cycle mechanism and its regulatory factors which are involved in carcinogenesis.


RESULT
Cell duplication is directed by a precise cellular machine. The engine of this machine is composed of the cyclin-dependent kinases (Cdks). Their function mainly consists of phosphorylating the pRb family of proteins to conduct the cell towards a series of events that end in generating two sister cells from one mother cell. The regulation of Cdk activity depends on several cellular proteins that are part of a major system that is able to sense extracellular factors and intracellular signals. Abnormalities in cell cycle regulation and in its checkpoints lead to development of malignant cells. Various components of the cell cycle machinery are mutated, overexpressed or eliminated in several human cancers. Some of them can be even classified as oncogenes or tumor suppressor genes.


CONCLUSIONS
It is necessary to design new antitumoral strategies able to target cells harboring such alterations, in order to understand the events that regulate the cell cycle and its disruption during oncogenesis.