Cancer cells do not respond normally to the body's control mechanism in that they divide abnormally without control, expanding to other tissues, and thus could lead to the death of the organism. Cancer cells do not exhibit density-dependent inhibition in that they do not require growth factors to reproduce successfully. Scientists do not know exactly what they require yet a few hypothesis include the fact that they may produce their own, their cell cycle is abnormal in that they do not require it. As a result they are said to be immortal. A cell is transformed into a caner cell when it is converted into a cancer cell. Usually at this point the organism's immune system recognizes it and acts to destroy it. However if the attack fails, and the cell survives, then it multiplies to form a tumor. If the tumor, or mass of cells remains in...