Tumor markers are helpful in diagnosing cancer and specifying what type of cancer the patient has. They are always combined with other testing to determine cancer. They are found in blood, tissues, and urine.
Tumor Marker
Tumor markers are things that tumor cells produce in response to cancer and some noncancer conditions. There is not a marker for every type of cancer, but there are a dozen or more tumor markers to date.
Screening
Screening for cancer can detect the condition early, usually before there are symptoms. Tumor markers are generally not specific enough to be a cancer screening tool. However, CA 125, a tumor marker, is at times used to try and detect ovarian cancer in women. It is used with other testing. Scientists are trying to develop tumor markers that are more senstitive and can be used for screening devices in the future.
Risk Markers vs. Tumor Markers
Tumor markers are indicators of a cancer presence. Risk markers are items that show that cancer is more than likely to occur. While risk markers show the ability for cancer to begin, tumor markers show that cancer has already begun. Risk markers are changes, alterations, or mutations in genetic code.
Use
Tumor markers are used to help the doctor measure treatment options, therapy, and in detection. While they cannot be used as a sole cancer diagnosis device, they can be used along with other diagnostic aids to suggest cancer. There are some cancers in which tumor markers can help doctors know what stage of cancer the patient has.
Tumor markers are helpful in researching and developing new and innovative cancer healthcare. For those looking to have earlier treatment and detection, tumor markers show that there is still much to learn and ways to learn.
National Cancer Institute
http://www.cancer.gov/cancertopics/factsheet/Detection/tumor-markers