Module 12: Figure cell cycle network and cancer
Multiple alterations of the signalling systems that control the cell cycle lead to the development of cancer.
Multiple genetic modifications occur during the development of a cancer cell. The mutated cell enters the cell cycle repeatedly to form a cancer. The proto-oncogenes that provide the positive signals to drive cells into the cell cycle are mutated into constitutively active oncogenes, whereas the tumour suppressors and the anti-proliferative signalling pathways are inactivated. In cancer, the cell-fate pathways of senescence, apoptosis and differentiation are also switched off by inactivation of the p53 surveillance system, thus leaving the developing cancer cells with no other option than to continue proliferating.