Tumor Marker for detecting breast, blood, lung and genetic cancer
Tumour Marker
Tumour marker is one of the concepts of the recent advances in the field of medical science. A tumor marker as the name denotes is something that is specific to a certain tumour. This is very significant as it is a non invasive method of detecting a tumour. Tumour marker can be defined as an antigen which is basically associated with a tumour also known as TAA. Antigens are special type of proteins which are complex in nature and when this protein is relatively very much restricted to only one type of tumour then this can be referred to as Tumour associated antigen or tumour markers.
Tumour marker to be ideal should basically have certain features, this includes restricted to one and only type of tumour that means the antigen should be released by one type of tumour itself. IT must be easy to detect even if the concentration is at a very low level. This is known as specificity and sensitivity of the tumour marker. The tumour markers concentration can also be used to detect the stages at which the tumour is progressing. Most tumours release proteins, in the form of macro molecules this is easily detected using an immunoassay. The uses of tumour marker is still limited as the sensitivity and specificity of a tumour marker is not so high which is needed to detect early tumours, hence it is currently being used for monitoring the recurrence of a tumour after anticancer therapy. Some of the common tumour markers used today are CEA, alpha feto protein, PSA and CA125.
CA125 is the name given for the tumour antigen which is highly specific for ovarian cancer cells. However the antigen is also known to be realised during any inflammation reaction that occurs in the peritoneum. TAG 72 is being used to localize the tumour especially in case of occult tumour deposits.
PSA Prostate specific antigen is basically a glycoprotein which is present in the normal epithelial cells of the prostate gland. In patients with advanced prostate disease one can use monoclonal antibodies and by defining the upper limit of normal serum level of PSA is detected. Sensitivity is very high than any other marker however specificity is not accurate as an elevated amount can also be found in a non malignant tumour. However the great importance of PSA lies in the monitoring for reoccurrence of the prostate cancer after treatment.
CEA-Carcinoembryogenic antigen, this is protein and a polysaccharide complex which is used to detect cancers of the colon. An immune assay for this specific antigen reveals that CEA is increased in the colon cancer however the specificity is of questionable value as it is also found in the normal fetal gut, liver and pancreas. It is also found to be present in high quantity in cancer of breast, pancreas, cervical cancer and cancer of urinary bladder.
Alpha feto proteins the name indicates it is a product from the cells of the fetal liver. It is detected in the patients suffering from hepatoma and yolk sac neoplasm. The biggest use of this marker is in diagnosis of gestational trophoblastic neoplasm.
