The role of cell cycle regulation in cancer

Abstract

During the past decades, cancer research has expanded rapidly due to the relatively high incidence rate of cancer and high death rate linked to it. The type and the extent of aggressiveness of particular cancers are determined by specific flaws in the cell cycle regulation. This study gives a detailed depiction of the cell cycle’s phases including the checkpoints being the G1 (GAP 1) phase, the G1/S (Synthesis) DNA damage checkpoint, the S phase, the G2 (GAP2) phase, the G2/M (Mitosis) DNA replication checkpoint, the M phase and the interphase. Regulation occurs at all the previous phases mainly through the formation of cyclins-CDKs (Cyclin Dependent Kinases) complexes. The latter control precisely the commencement and completion of the specific events leading to cell duplication and division by activating various genes such as the Rb (Retinoblastoma) gene. CDKs’ activity is in turn regulated by various factors such as phosphorylation, controlled degradation of cyclins, regulated synthesis of both CDKs and cyclins by growth factors and cytokines, as well as by CKIs (Cyclin-dependent kinase inhibitors) such as p15, p16, p18, p19, p21, p27 and p57. The balance between tumour suppressor genes such as p53 and Bax and antiapoptopic genes such as Bcl2 and IGF-BP3 has also been demonstrated with a particular focus on p53-"the guardian of the genome".