Cancer is a disease that kills one out of every five peope in the world.
It is a disease of the cell cycle. Cancer cells have no control system to monitor their division, and therefore, they divide uncontrollably. The result of this uncontrollable division is the collection of cells into one large mass called a tumor. Luckily, not all tumors are cancerous. A benign tumor is essentially made up of normal cells and can easily be removed by surgery.