Cancer is not a single disease, nor does it have a single cause. There are more than 200 different types of cancer, each requiring treatment specifically tailored to treat patients with that type of cancer.
In a normal cell, a series of precise and orderly mechanisms dictate the speed and timing of cell growth, division and death. But sometimes, this cell cycle can go awry. External factors, such as carcinogens, toxins and UV rays, can damage the cells’ DNA, triggering the loss of the control mechanisms that dictate when and how fast certain cells divide and/or die. Heredity can also play a role in some types of cancers, particularly when combined with these external triggers.
For more information and breast cancer background, go to the following link:http://www.cancer.gov/cancertopics/pdq/treatment/breast/patient