The Facts
Leukemia is a type of cancer that causes the body to make too many white blood cells, causing a breakdown of the body's immune system. This uncontrolled production doesn't give these cells a chance to properly mature. The immature cells either won't function well or will interfere with the production of other white blood cells. Normally, these cells play an important role in the body's natural defense system. They target and destroy foreign invaders like viruses and bacteria. White blood cells are made in the marrow - the spongy core - of your bones.