The next question naturally would be whether these cancers can be prevented. Maintaining a healthy lifestyle, regulating diet and sleep habits, de-stressing from time to time using yoga or the occasional holiday, staying away from addictive substances such as alcohol and tobacco can go a long way in preventing cancer. Cancer, in short, is when a cell is subjected to external stress to an extent in which it loses its internal regulation. Think of it in a way where someone is constantly teasing or taunting you, there comes a point where you lash back at that person. Similar happens in cancer, where the cell loses its innate function due to persistent external stimuli, becoming an angry abnormal cell. This then starts dividing and spreading to other parts of the body forming colonies of such cells which prevent the normal body cells from doing their regular functions.