The landmark event of cancer: escape the fate of cell death

    In normal tissues, the new generation of cells maintain a balance through cell division and cell death. Older cells gradually deteriorate over time and enter a process called apoptosis. Apoptosis is a very orderly process. 

    In this process, the cell's genome and all its genetic information will be damaged. Cells become fragmented, and these fragments can be digested and removed by neighboring cells (called phagocytes). This is a normal and necessary process for us to use brand new and healthy cells for some renewal of the body.

     There are checkpoints in the cell cycle that are used to identify and eliminate abnormally dividing cells. These checkpoints are responsible for preventing the development of cancer cells, because cancer cells can grow and divide in a different way than normal cells. Those cancer cells that can pass these tests can escape the cell death signals triggered by their abnormal behavior.

    The escape of cell death is accompanied by the formation of tumors caused by continued cell division. Many of the chemotherapeutics discussed in the cancer treatment section work by forcing cancer cells to undergo a process of apoptosis.

    The process of apoptosis includes nuclear fragmentation and the formation of cell debris, which are shown in the animation below.