The cell cycle is a highly ordered process that results in the duplication and transmission of genetic information from one generation of cells to the next. The regulation of the cell cycle must ensure that the events in each phase are complete before moving to the next phase. The development of cancer is a complex process that requires the accumulation of damage to the cell's growth controlling genes, including damage to the tumor suppressor genes and proto-oncogenes. Tumor suppressor genes are normal genes that slow down cell division, repair DNA, and tell cell when to die. While proto–oncogenes tell the cell to stay in the cell cycle and continue to divide. Several mutations have been observed in genes coding the different proteins involved in the cell cycle. This review highlights the interrelation ship between cell cycle deregulation and cancer and the development of different cancer therapies eg. Gene therapy and cancer vaccines.