Tumor markers
Tumor markers are substances that can be found in the body when cancer is present.
Some tumor markers are found in blood, but others are found in urine or other body fluids. Still others are found in tumors and other tissues.
They may be made by the cancer cells themselves, or by the body in response to cancer or other conditions.
Most tumor markers are proteins, but some newer markers are genes or other substances.
There are many different tumor markers. Some are linked only to one type of cancer, while others can be found in many cancers.