HOW does cyclin help in understanding how and why cancers form?
The discovery of the cyclin-dependent kinases key regulators of the cell cycle at last clarified the basis of cell cycle control, and hence of the basis of cell proliferation. You could say that they are the `cell cycle engine’. But although the car’s engine is necessary for it to move, it is the driver (cyclin) who decides where to go. So it has not really shed a lot of light on the origin of cancer. What happens to the check points that are supposed to stop an abnormal cell from dividing or growing? There is a school of thought that suggests that cell cycle `checkpoints’ are defective in tumour cells. Some scientists believe that the mitotic checkpoint and spindle assembly checkpoints may be altered, so that cells accumulate additional DNA damage in the form of broken chromosomes, the kind of thing that provides a seedbed for the evolution of cancer cells What happens to the checkpoints when the first cancer cell forms? In principle, the DNA damage checkpoint ought to prevent cells e
