Klin Onkol 2000; 13(1): 13-16.
Summary: The development of human cancers is frequently associated with the inactivation of two major tumour suppression pathways represented by the retinoblastoma protein (pRb) and by the p53 protein. Growth control in mammalian cells is accomplished largely by the Rb protein regulating exit from the G1 phase and the p53 protein triggering growth arrest/apoptosis in response to cellular stress. Interactions between these two regulatory pathways may be mediated through the inhibitor of cyclin dependent kinases (CKI) protein p21WAF1, which is a target of p53 transactivation, as well as a factor that influences the functional status of Rb protein. The CKI p21WAF1 also plays a critical role in the control of cell proliferation by modulating the activity of cyclin/CDK complexes in response to different intracellular and extracellular signals.
