What Happens in Biological Therapy

Raphael Catane, MD, and Malcolm S. Mitchell, MD 
Adapted for the Canadian edition by Ian Quirt, MD 

Biological therapy is a relatively new way to treat cancer. It is based on the idea that the human immune system , which is designed to eliminate and destroy any foreign substance
found inside the body, can play a role in destroying cancer
cells.
    There are several problems with this approach. One
of the biggest is that the immune system doesn't
always treat cancer cells as "foreign." It is easy
for the system to recognize bacteria or viruses,
since they are completely different from normal
human cells. But the difference between a tumor
cell and a normal cell is small.