HOW DOES CANCER START?
Cancer is the general name for a group of more than 100 diseases. The body is made up of trillions of living cells, and normal body cells are generally dominant, growing, reproducing and dying in an orderly way. Cancer starts when abnormal cells— which are always present— begin growing rapidly and invading other, normal cells.
DNA is in every cell and it directs all its actions. When DNA in a normal cell is damaged, the cell either repairs the damage or dies. In cancer cells, damaged DNA is not repaired. The cell doesn’t die, but goes on to make new cells with the same damage.
Although DNA damage may result from something obvious like cigarette smoking or sun exposure, it is actually rare to know exactly what caused any one person’s cancer.