Fact 1: Antigens are found on cancer cells and the cells of transplanted organs.

Fact 2: Antigens are proteins foreign to the body.

Given the two facts above, answer the question "proteins foreign to the body can be found where?" with the following options: 
- in the lymph nodes
 - in nerve cells
 - in the kidneys
 - on cancer cells
 - critical organs
 - mouth of rivers
 - Earth orbiting the Sun
 - the skin


 

    on cancer cells     