Cancer markers, also referred to as tumor markers, have results that aren't always reliable in diagnosing cancer. However, they are helpful in monitoring results of cancer treatment, as they elevate or decrease after treatments. These markers can indicate certain cancers, but not conclusively.
History
Cancer markers were discovered in 1965 with the first blood test for cancer. Based on pregnancy blood tests, cancer cells were found to elevate certain proteins, numbered starting in 1970 as CA15-3 for breast, CA125 for ovarian and CA19-9 for colorectal and pancreatic.
Protein
Certain proteins are given off by the cancer cells or by the body's defense against them. Not all cancer cells give off proteins, and not all tumor markers are caused by cancer.
PSA Levels
Widely used cancer markers are PSA, or prostate-specific antigens. Prostate cancer has high PSA levels. Other prostate conditions might generate tumor markers, and some prostate cancer patients may not have elevated PSA levels.
Hormone Receptors
Hormone receptors are cancer markers used for cancer treatment decisions. Breast cancer that reacts to estrogen and progesterone, which occurs in two out of three cases, can be treated with hormone therapy like Tamoxifen.
Immunoglobulins
In the body, there are many different immunoglobulins, antibodies that are blood proteins made by the immune system to fight cancer cells. These are not considered tumor markers except in the case of bone marrow cancer, which can cause too high a level of one of the immunoglobins to be found in the blood and urine.
Tags: cancer cells, tumor markers, Cancer markers, cancer treatment, used cancer
