What Are Tumor Markers?
A tumor marker is a substance comprised of proteins produced by the cancer tissues in the body, or on occasion, depending on the type of cancer, by the body in its response to growing cancer. Tumor markers may be detected in tissue samples, urine samples, and blood samples. Some other procedures and tests may be used to help detect different forms of cancer. Some tests and procedures may also detect whether or not a person is predisposed to a recurring type of cancer or a specific cancer type. Tumor markers may also be used alongside imagery testing and other procedures.
In recent years, the research on tumor markers has broadened to include newer tests that may be more accurate and include genetic materials such as RNA and DNA. Genetic changes are predominant in certain types of cancer and may help to determine whether or not a person has specific tumor markers. This can help to determine a prognosis and guide the patient to a targeted treatment that is more accurate in treating specific types of cancers. Just because a person has specific genetic changes doesn't necessarily mean that they will have cancer, only that they may be predisposed to cancer and should monitor their health more closely to ensure that they don't get cancer.
Advances in technology have led researchers to more tests that can help to evaluate a variety of genetic markers and panels of markers together. This can offer more detailed information that tells the potential characteristics of specific tumors, which includes more traditional tumor markers. Others are currently evolving to expand clinical trials wherein more information will become available to researchers. It's likely that this will offer greater effectiveness in treatment protocols in the future and will, in time, replace less useful procedures with more advanced technology.
Limitations
Of course, everything has limitations, and tumor marker tests are no exception. Many of the tumor markers could be elevated for reasons other than cancer. Some of the markers are specific for a specific type of cancer, while others are seen in a variety of different types of cancer. Some may show up due to pregnancy or other medical conditions.
Not everyone who shows a specific tumor marker will have elevated levels of the corresponding tumor markers. Not every tumor marker is going to show up in each type of cancer. Thus, tumor markers aren't the only diagnostic tool used for diagnosing cancer. They do, however, offer additional information that helps diagnose a patient, especially if tested for in conjunction with their genetic mapping and medical history. Physical exams are also vital to the final results of the lab and imagery testing.
How Are Tumor Markers Utilized?
There are a variety of ways that tumor markers may be utilized. They're not used alone and will be dependent upon the type of cancer that is being diagnosed. They may often be utilized in conjunction with tissue biopsy, blood smears, and possibly bone marrow tests to help determine the severity of the condition. While not definitive in and of themselves, it is vital that tumor markers be used in the screening to determine the severity of cancer.
When screening for cancer, most tumor markers aren't sensitive or specific enough to be the main determining factor. They're not suited to determining whether or not the general population has specific cancer. They are, however, helpful to determine if someone is at high risk for specific cancers.
When diagnosing someone who has symptoms of cancer, they're helpful to detect the presence of cancer and help differentiate cancer from other symptoms.
In determining the stage and severity for someone with cancer, the elevations of tumor markers can help determine whether or not cancer has metastasized to other organs and tissues and the extent of the spread.
In determining the prognosis, many tumor markers can show how aggressive cancer is likely to be. They can help to guide a choice of treatment. Many tumor markers give information that may help determine the course of treatment.
When monitoring treatment, tumor markers can help to monitor the effectiveness of the treatment. As marker levels drop, it will denote how effective the treatment is. It's important to factor in other details as well. Just because tumor markers are lower doesn't necessarily mean that the treatment is working effectively. If the markers are low after treatment but begin to rise, it may indicate a recurrence or that a different course of treatment is required. There could still be cancer in the body, or it may be recurring.
Examples Of Tumor Markers:
AFP or Alpha-fetoprotein: Liver, ovarian, and testicular cancer may have these markers. These markers may also be elevated during pregnancy or if the person has hepatitis.
ALK Gene Rearrangements: Cancers that are associated with such cancers as non-small cell lung cancers or anaplastic large cell lymphoma.
B-Cell Immunoglobulin: These cancers are associated with B-cell lymphoma. The markers can help to determine the diagnosis and monitor the treatment for recurrence. They can detect the changes in the specific genes found in B cells.
Beta-2 Microglobulin: Myeloma, some of the leukemias, and some lymphomas will have these markers. They may also show up in patients with kidney disease.
BCR-ABL: Chronic myeloid leukemia or CML and BCR or ABL positive acute lymphocytic leukemia or ALL show these markers.
CA 15-3 and CA 27.29: These two tests both test for the same genetic marker associated with Breast cancer. These are also likely to be elevated with other cancers such as lung or ovarian cancer and benign breast conditions. Endometriosis and hepatitis will also show up with these genetic markers.
CA 19-9: Pancreatic, gallbladder, colon, stomach, and sometimes bile ducts [AZ1] will show up with this type of tumor marker. It will also show other digestive tract cancers and non-cancers, including thyroid disease, inflammatory bowel disease, and other conditions.
CA-125: This tumor marker is associated with Ovarian Cancer. It can help to diagnose and monitor the treatment for ovarian cancer. It shows endometrial, peritoneal, and fallopian tube cancers as well as PID and uterine fibroids. It can also show up in pregnancy.
Calcitonin: Medullary thyroid carcinoma or MTC and Hyperplasia C-cell shows up with this tumor marker. It can also elevate with leukemia and lung cancer.
CEA: Colon, pancreatic, breast, lung, and ovarian cancer will show this marker as well as medullary thyroid cancers. It can identify the stage of cancer, and it can help to determine the prognosis as well as monitor the treatment. It also elevates with RA, COPD, hepatitis, colitis, in smokers, and pancreatitis.
Chromogranin-A: Neuroendocrine tumors such as neuroblastoma and carcinoid tumors show this marker. It can help to monitor the treatment protocols and monitor the potential for recurrence. It's very sensitive to carcinoid tumors.
DCP: If a cancer is associated with Hepatocellular carcinoma or HCC, this can help to monitor the treatment protocol and the potential for recurrence. It's often used alongside the imaging studies for AFP, AFP-L3%.
EGFR Mutation: Non-small cell lung cancers, occasionally head and neck cancers, are prone to this marker. This marker is used to monitor treatment protocols and recurrence.
Estrogen and Progesterone Receptors: Breast cancers associated with this marker. Used to help determine the prognosis and to guide the treatment protocol. It increases with all hormone-dependent cancers.
Fibrin/Fibrinogen: Bladder cancers show this marker. Again, it's used to monitor treatment and recurrence.
Gastrin: G-cell hyperplasia and gastrin tumors show this marker. It's also used to aid in diagnosing Zollinger-Elison syndrome.
hCG: Testicular and trophoblastic diseases as well as choriocarcinoma, germ cell tumors show this marker. It also elevates during pregnancy.
HER2: Esophageal, gastric, and breast cancer show this marker. It can help to guide treatment protocol and determine which drugs are working best on the cancer cells.
JAK2 Mutation: Leukemia myeloproliferative neoplasms, polycythemia vera can all show gene mutations for such cancers.
KRAS Mutation: Colon, non-small cell lung cancers can all show up with this marker.
Lactate Dehydrogenase or LD, LDH: Testicular and other germ cell tumors will show this marker. It can identify the stages as well as guide the treatment protocol. It will also elevate in other conditions, including neuroblastoma, lymphoma, melanoma, and more.
Monoclonal Immunoglobulins: Waldenstroms macroglobulinemia, multiple myeloma, and other similar types of cancer can show this marker. It's a protein electrophoresis or a serum-free light chain.
PSA: Prostate-specific antigen is associated with prostate cancer. It's used to screen for prostate cancer and can help in the diagnosis and treatment protocol. Elevated levels can show benign prostatic hyperplasia as well as prostatitis.
SMRP or Soluble Mesothelin-related peptides: Mesothelioma, which is rare cancer that is associated with exposure to asbestos, shows this marker. It can help to determine the aggression of cancer as well as the treatment protocol alongside imagery testing.
T-Cell Receptors Gene Rearrangement: T-cell lymphoma. Diagnosis and monitoring of treatment for recurrence. It can detect the rearrangement of the genes that are specific to T-cell lymphoma.
Thyroglobulin: Thyroid cancers show this marker. It's used to monitor treatment and after the thyroid is removed to determine if further treatment is required.
Breast cancer gene expression treatments are cancers that are in the breast or the breast tissues. It can help to monitor the treatments for breast cancers. It can show whether or not there may be a recurrence and guide the treatment. It can also evaluate the risk of recurrence and whether or not someone will require chemotherapy to treat breast cancer.
