Tumor marker is the name given to certain chemicals within the body that may be increased when there is any cancerous growth in the body. This may be manufactured by the body’s immune system or may be released by the tumor. Insome cases, it is the level of hormones thatcan be used to determine the possibility of a tumor. In all cases, it helps to determine the type of cancer that has spread within the body. This is because each marker points towards certain types of cancer. However, it can be increased in some other cases too and a careful analysis of other correlating evidence is a must by a trained professional. Various markers have been identified by now that can help in identification as well as understanding the vengeance with which the disease has struck. This is important in deciding the course of subsequent treatment.
Antidiuretic Hormone (ADH): This is used to detect small cell lung cancer and adenocarcinoma, on the other hand it is also raised during pneumonia as well as porphyria, a blood disease.
Normal levels are 1 – 5 pg/ml.
Alpha-feto protein (AFP): Increased levels of this protein indicate liver cancer and cancer of germ cells in ovaries in women and testis in men. It is expected to rise, among other things, during pregnancy and non cancerous diseases of the liver.
Normal AFP levels are 10 ng/ml (nanogram per milli liter). AFP levels more than 4000 ng/ml is a sign of liver cancer.
Anaplastic lymphoma kinase (ALK): The change in this gene is generally found in some types of lung cancer. This requires testing of the tissues of the tumor.
BCR-ABL: This abnormal gene is observed in Chronic myeloid leukemia (CML) and is generally used to verify the diagnosis and as a follow up during treatment.
Beta-2-microglobulin (B2M): Generallyraised in multiple myeloma, CLL and a few lymphomas, as well as other conditions like hepatitis and kidney diseases. It is also ordered to check the response to treatment. High levels are not a good sign.
Normal blood levels of beta-2-microglobulin are usually below 2.5 mg/L (milligram per liter)
Bladder tumor antigen (BTA): This is found in the urine and is mainly indicative of bladder cancer, though certain conditions like recent surgery, UTI as well as cancer of the ureters and the kidney can also lead to a false positive.
BRAF: Mutation in this gene is seen in melanoma, colorectal cancer and thyroid cancer. It is found in the tissues of the tumor itself.
CA 15-3: This is a clear marker of breast cancer, but unfortunately is not a very sensitive indicator. Thus it does not help in an early diagnosis and is mainly used as a follow up during treatment. It can also be high in lung, pancreas plus ovarian cancer. Besides this, it may also rise in other diseases like hepatitis, diseases of the ovaries and breast that are not cancer and endometriosis.
Normal blood levels of CA 15-3 are less than 30 U/ml (units per milliliter)
CA 19-9: The carbohydrate antigen identified as CA 19-9 generally indicates the presence of cancer of the pancreas or colorectal cancer. It may also indicate the presence of other benign conditions like pancreatitis, IBS and ulcerative colitis. It is also used as a follow up during bladder cancer.
Normal blood levels of CA 19-9 are below 37 U/ml (units per milliliter)
CA 27-29: This is again used for examining the effect of the treatment being given for breast cancer rather than to diagnose the disease as it is raised in cancers of other organs too. It is also likely to be raised during the first three months of pregnancy.
Normal blood levels of CA 27-29 are usually less than 40 U/ml (units per milliliter)
CA 125: The presence of this antigen points towards ovarian cancer. Unfortunately a higher level of this is also present in a number of benign conditions. Besides, pregnancy can lead to a false positive.
Normal blood levels of CA 125 are usually less than 35 U/ml (units per milliliter)
Calcitonin: The presence of this hormone is detected in thyroid medullary carcinoma, a type of cancer that occurs in the tissue lining the affected organ. This tumor marker can be used for early diagnosis.
Normal blood levels of calcitonin are below 5 to 12 pg/ml (pictograms per milliliter) In medullary thyroid carcinoma (MTC) blood calcitonin levels are greater than 100 pg/ml.
Calretinin: The presence of calretinin has been shown in mesothelioma and it is also utilized to distinguish among various types of lung tumors as well as brain tumors.
Carcinoembryonic antigen (CEA): A rise in this antigen indicates colon cancer. However, it is important to interpret the results of this test cautiously as cigarette smokers may have a false positive. Besides, it is likely to be raised in a number of other cancers like lung, breast, melanoma as well as other organs of the body. It is therefore used as a measure of response to treatment.
Normal blood level of CEA for non smokers is less than 3 ng/ml and for smokers less than 5ng/ml.
CD34 & CD117: These help to differentiate between different types of gastrointestinal stromal tumors.
Chromogranin A: This is produced by various neuroendocrine tumors like small cell lung cancer and carcinoid tumor. However, proton-pump inhibitors (lansoprazole) may also lead to raised levels in the body.
Cytokeratin: Cytokeratin profile helps to differentiate among various tumors because each cytokeratin is specific to a particular organ/tissue. Thus the study of these proteins helps to diagnose various types of carcinomas.
Desmin: Testing for this protein helps to detect various types of muscle sarcoma, that is, cancer of certain muscles.
Epidermal growth factor receptor (HER1/EGFR): The test for this protein is carried out on tissue and helps to gauge how aggressive the cancer is likely to be. In other words, it is not used as a diagnostic tool but is used to guide the treatment to be given.
HE-4: This blood test is again not meant to confirm the diagnosis of cancer, but is used as a follow up during treatment of ovarian cancer.
HER2 (or HER2/neu, erbB-2, or EGFR2): The tissue of the cancerous growth is tested for this protein called human epidermal growth factor receptor 2. The higher the level, the faster the cancer will spread and treatment focuses on giving drugs that reduce this protein.
Hormone receptors: It has been observed that some breast cancers are hormone sensitive and testing for levels of estrogen and progesterone can help to guide the treatment of breast cancer in women.
Breast tumor cells are tested for hormone receptors not the blood sample. Breast cancer cells with estrogen receptors are called as ER positive and with progesterone receptors are called ad PR positive.
Human chorionic gonadotropin (HCG)/ Beta-HCG: If HCG is raised in the body, other than pregnancy, then it can be indicative of cancer of the chest, ovaries and testicles. It is also used to check for recurrence of cancer.
Immunoglobulins: These antibodies are produced in the body as a response to certain diseases. A high level of a single type of antibody can help to diagnose bone marrow cancers.
KRAS: This gene is tested to select the right drugs for treatment of certain cancers. It has been found that mutations in this gene make some medicines ineffective in the fight against cancer.
Lactate dehydrogenase (LDH): This can be used as a marker for testicular cancer but unfortunately, levels of this enzyme tend to rise in other non-cancerous diseases. It is more appropriate to understand the possible outlook, recurrence and the course of the treatment.
Neuron-specific enolase (NSE): This is used to study the response to treatment in patients of neuroendocrine cancers. It is not sensitive enough to be used as a diagnostic tool.
NMP22: This is a urine test and is used to check for recurrence of bladder cancer.
Prostate-specific antigen (PSA): This is used to screen for prostate cancer, though PSA levels may also be raised to some extent by inflammation and ejaculation.
Normal blood PSA levels are less than 4 ng/ml (nanaogram per milliliter). Levels higher than 10 ng/ml indicates prostate cancer.
Prostatic acid phosphatase (PAP): This was earlier used totest for prostate cancer, but the PSA test has taken its place. Itis now utilized for the diagnosis of lung cancer and multiple myeloma.
S-100 : Testing tissues for this protein helps to confirm the presence of melanoma while levels in the blood are likely to be raised if the melanoma is spreading to other parts.
Soluble mesothelin-related peptides (SMRP): Mesothelioma, which is a rarely occurring lung cancer, can be followed with this test.
Thyroglobulin: This may be high due to any thyroid disease as well as cancer of the thyroid. It is therefore used for checking the efficacy of the treatment as well as any comeback by the cancer.
Written by: healthplus24.com team
Date last updated: September 28, 2013