Internal Medicine

Tumor markers

introduction

Tumor markers are substances that can be measured in the blood and for the presence of Tumors can point out. They are mainly produced by malignant cells in the body and can thus point the way for a diagnosis be. Tumor markers can either be from tumor be synthesized themselves, or arise as a reaction of the tissue.
Since they do not always reliably correlate with the presence of a tumor, the tumor markers are usually not used for diagnosis. In addition, most tumor markers also rise in certain benign diseases and are therefore not useful for early diagnosis of a tumor disease. However, there are some markers that can be used to monitor the progress of a Tumor treatment can be used and here also allow reliable statements about the prognosis and effectiveness of the therapy. There are many different tumor markers that are specific to certain organs.

CEA

The C.arcinoembryonal A.ntigen (short CEA) was first used as a tumor marker 1965 isolated from colorectal carcinoma cells. It is a family of Glycoproteinswhich of the CEA building cells into their own cell membrane and also release this into the blood.

For this reason, CEA can be detected both in the corresponding cells and in the blood. Since this is a very unspecific tumor marker, it cannot be used for the early diagnosis of a tumor. However, it has proven itself in follow-up care and therapy control. CEA is particularly specific for colorectal carcinoma and thyroid carcinoma. However, there are also benign conditions like inflammation of liver, stomach, pancreas and lung, as well as the alcohol-induced Cirrhosis of the liverwhich can lead to a CEA increase. Smokers can also have elevated levels of CEA in their blood. However, permanently elevated CEA values indicate a malignant tumor.

HCG

The Humane C.horionGOnadotropin (HCG) as a tumor marker is used too Beginning of a pregnancy produced by fetal cells. It is used to stimulate the ovaries, which stimulates the production of hormones and thereby preserves pregnancy.

If there is no pregnancy, increased HCG values indicate a malignant tumor of the ovaries, but also benign ulcers of the ovaries, or in men to one Testicular tumor down. This is usually a Chorionic carcinoma. Even with one Liver tumor (Hepatoblastoma) in children, increased HCG levels are detectable. The mole of the bladder in women is an example of benign diseases that are associated with increased HCG levels.

AFP

The Alpha1 fetoprotein serves as Tumor markers at Hepatocellular carcinoma and germ cell tumors. It becomes in the fetus from the 4th week in the liver formed and serves here as a transport protein. After birth the production of the Alpha1 fetoprotein almost completely set and can then reference a tumor be. In addition to tumor diseases, it can also indicate a defect in the fetus if the Alpha1 fetoprotein - value in the Amniotic fluid of pregnant women is significantly increased. In principle, the Alpha1 fetoprotein - Value is better suited for follow-up than for early diagnosis. In combination with an increased HCG value (human chorionic gonadotropin), the AFP value serves as a tumor marker to control germ cell tumors, especially in children.

CA 19-9

The tumor marker Carbohydrate Antigen 19-9 is a Glycoprotein, which especially at Pancreatic cancer (Pancreatic carcinoma) is produced. It has a half-life of 4 to 8 days and is used to monitor the progression of pancreatic carcinoma. According to studies, the CA 19-9 concentration in about 50% of patients with a tumor 3cm there is an increased value in about 90%. The height of the tumor marker correlates with the size of the tumor. Increased levels are also found in around 70% of bile duct tumors Carbohydrate Antigen 19-9 Value.

CA 72-4

Of the Tumor markers Cancer antigen 72-4 is mainly used as a tumor marker Gastric cancer utilized. It is a protein that occurs physiologically on many surface cells.

But also ovarian cancer (Ovarian cancer) show an increased Cancer antigen 72-4 Value on. Since this value is also at Pneumonia and Cirrhosis of the liver is increased, this value cannot be directly attributed to the presence of a carcinoma either. In very rare cases Cancer antigen 72-4 be increased even in healthy people. Although the CA 72-4 value is particularly sensitive to mucinous ovarian cancer, the value in the guidelines of the German Cancer Society is generally used for monitoring the progression and treatment of colon cancer.

CA 15-3

The Cancer antigen 15-3 is also called a mucin-1 (MUC 1) tumor marker. It is a mucin found in all vertebrate membranes. With epithelial Tumors, Adenocarcinoma, Lymphoma or that multiple myeloma the cancer antigen 15-3 is clearly overexpressed and can thus be used as a tumor marker. In practice it is used as a marker to monitor the progress of Breast cancer patients utilized. However, the sensitivity is only around 60-80%.In addition to this follow-up, mucin-1 is also used as an approach for newer therapies in cancer therapy.

CA 125

The tumor marker CA 125 is just like that CA 15-3 a sugar-protein molecule, which is mainly at Ovarian cancer (Ovarian cancer) Has meaning. The measurement of the CA 125 is of great importance, especially in follow-up, and can be used as a relatively specific marker to detect a relapse.

German cancer experts determined that a repeated normal CA 125 Value after ovarian cancer can replace other more complex examinations. There are also some benign diseases, such as cirrhosis of the liver, acute inflammation of the pancreas and inflammation of the gallbladder, which can cause an increased Ca 125 level.

NSE

The neuron-specific enolase as Tumor markers is an enzyme of glucose metabolism and is found in various sub-forms in the nerve cells of the Brain, formed in peripheral nerve tissue and in so-called neuroendocrine tissue. The formation of the enolase in these hormone self-producing (neuroendocrine) tissues is used for tumor control. For this reason, the NSE is significantly increased, especially in small cell lung cancer and tumors of other neuroendocrine tissues. However, the NSE value also rises in the event of trauma Brain, at Brain tumors or the Creutzfeld-Jakob disease on.

SCC

The Squamous cell carcinoma antigen (engl. Squamous cell carcinoma antigen) is a sugar-protein molecule and, as a tumor marker, part of squamous cell carcinoma cells. Squamous epithelia are found in a wide variety of organs, for example as keratinized squamous epithelium on the skin or on mucous membranes.

Renal failure, Kidney failure, Skin disorders, Cirrhosis of the liver or one Inflammation of the pancreas (Pancreatitis) can show increased SCC values although these are not tumor diseases. Squamous cell tumors of the cervix, the esophagus, of the lung or des Rectum are examples of squamous cell tumors and can therefore show elevated SCC values. Here, too, the SCC value primarily indicates renewed disease activity after successful therapy. However, the SCC value is not recommended as a tumor marker in the guidelines of the German Cancer Society.

PPE

The tumor marker prostate-specific antigen is an enzyme that is formed in the glandular epithelium of the prostate. Physiologically, it is added to the ejaculate in small quantities and serves to liquefy the semen coagulum. The formation of PSA takes place under the control of androgens.

Today PSA is one of the most important prostate-specific tumor markers. Since PSA can also be detected in healthy individuals or in patients with benign prostate enlargement (benign prostatic hyperplasia), the PSA value is considered a tissue marker, not a pure tumor marker.

A PSA value between 4-10 ng / ml correlates with the occurrence of prostate cancer in 25% of cases. If the PSA value is above 10ng / ml, the probability of prostate cancer is 50 to 80%. The other PSA increases correlate with inflammation of the prostate, a benign enlargement of the prostate or a prostate infarction. Correspondingly, screening for prostate cancer using the PSA value is not specific enough to replace other examinations.
However, the PSA value can be very meaningful after therapy. A previously increased and steadily decreasing PSA value is a clear sign of remission after a tumor disease. Since an increase in PSA could not always be correlated with the presence of a tumor in studies, the PSA screening is not covered by the health insurance. Nevertheless, it is possible for men to have an annual screening, provided they pay for it themselves.

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Summary

Tumor markers are synthesis products of Tumor, or the body's own tissue and can be used to detect tumors. Many different tumor markers are known today, the most important of which are explained in the text.
Due to their very low specificity, tumor markers can generally not be used for diagnosis or tumor search. Too many other benign diseases or inflammations can also result in elevated levels of one Tumor markers accompanied. Nevertheless, the PSA value in particular is used by some doctors to screen for a prostate tumor. However, the significance of this could not be proven in studies and is therefore controversial in professional societies. Most of the other tumor markers can mainly be used to monitor therapy and progress.
Here, the tumor markers can be very meaningful and in part replace other, more complex examinations. In contrast to this, false positive results in preventive care can lead to numerous, possibly stressful examinations, as no tumor marker can provide certainty about the presence of a tumor. The specialist societies for cancer research had to distance themselves from the hope of having found a simple and relatively gentle form of early tumor detection in tumor markers.