Almost all the cells in our body need to be replaced on a regular basis. Some cells are replaced every few days while others live for many years before dividing and forming new ones. Cancer refers to the process of uncontrolled cell division and involves more than 100 different diseases, which are named after the area where the tumor occurs. Cancer prevention refers to the effort to control the risk factors that can lead to the disease. Knowledge of risk factors, including genetic predisposition, hormonal imbalance, environmental toxins, immune system disorders, and other factors, are key to preventing cancer.