A biopsy is a procedure that removes a small piece of living tissue from your body. The tissue is examined with a microscope for signs of damage or disease. Biopsies can be done on all parts of the body. A biopsy is the only test that can tell for sure if a suspicious area is cancer. But biopsies are performed for many other reasons too. There are different ways to do a biopsy. A needle biopsy removes tissue with a needle passed through your skin to the site of the problem. Other kinds of biopsies require surgery.