Cancer is a demon that doctors have desperately tried to exorcise for decades. It is the body turned against itself, where the natural programming of healthy cells runs amok. The dysregulation of the orderly signaling pathways is linked to the balance between cellular growth and cellular specialization of the cell life cycle. The result is unrestrained cellular proliferation accumulating into large tumors that interrupt the normal functions of vital organs.
Since cancerous cells are derived from normal cells of the body, the human immune system does not see them as disease because the immune system is trained only to distinguish between “self” and “non-self.” This prevents the body from attacking itself, though disorders where this mechanism fails are known as autoimmune diseases.