What happens when apoptosis goes wrong?
Apoptosis could be the key to understanding some common illnesses. In a healthy body, the number of cells stays constant. Millions of new cells are produced every second, and millions of others are lost or kill themselves. A failure in apoptosis could lead to cancer - uncontrolled growth. Excessive apoptosis could cause wasting away as in Alzheimer's and Parkinson's diseases. Some viruses also exploit apoptosis - the AIDS virus may persuade immune cells to kill themselves.