Tumor markers are molecules which indicate the patient has a tumor. This is indicative when their concentration values in the blood, the urine or in tissues are higher than usual. Detection and measurement of Tumor markers is used in the diagnosis and treatment of cancer when determining the success of therapy.
The ideal tumor marker
To this day, more than 100 tumor markers are discovered, but no more than 20 of them are being used in laboratory practice. It is worth mentioning that there is no ideal tumor marker which would give precise information on the type of the tumor (whether it is malignant or benign) and an information on the stage of disease. Elevated tumor markers’ values can occur in cases of certain inflammatory processes and those decrease when the inflammation ceases. However, in case of tumors, their value never decreases, on the contrary, it constantly increases until the disease is detected and the appropriate therapy is selected. Measuring the values of the tumor markers must always be utilized in conjunction with other diagnostic procedures.
Types of tumor markers
Most tumor markers are not specific for one type of cancer, i.e. a tumor marker can have elevated values for different types of cancers. The following tumor markers are commonly used in the diagnosis and monitoring of the development of some types of tumors:
CEA (the carcinoembryonic antigen) - first discovered in patients suffering from colorectal cancer. However, elevated levels of this tumor marker are detected in other types of cancers such as: melanoma, lymphoma, thyroid cancer, stomach (gastric), cervical, ovarian, kidney, lung and breast cancer. Elevated levels of this marker can also be found in certain diseases such as cirrhosis of the liver, inflammation of the colon or the thyroid gland and in chronic inflammatory lung diseases. CEA tumor marker is commonly used in the diagnosis and treatment of colorectal cancer.
CA 15-3 - elevated levels of this marker indicate benign or malignant breast tumor. However, each breast tumor does not increase the values of CA 15-3, such in the case of the tumor's initial stage. Merely 30 % of patients with localized tumors and 50 to 90 % of patients with metastatic breast cancer have elevated CA 15 - 3.
CA 125 is a tumor marker whose elevated values indicate various benign gynecological diseases, ovarian metaplasia, endometriosis, uterine myomas or inflammation of the cervix. According to the recommendations of the World Association of gynecologists and obstetricians, this marker exhibits great importance in determining different gynecological conditions, particularly in monitoring the treatment progress and general condition in patients suffering form ovarian cancer. Elevated levels of this marker are detected in patients with cirrhosis and liver inflammation.
CA 72-4 is a tumor marker that detects malignant neoplasms of the pancreas, ovaries, breasts, lungs and other gastrointestinal tumors, when elevated. It is a highly sensitive tumor marker that in conjunction with CEA and CA19- 9 is used as a predictor of malignant changes in the gastrointestinal tract.
CA 19-9 is a tumor marker with low values in adults. It originates from the liver, the lungs and the pancreas gland. Elevated levels of this tumor marker predict benign and inflammatory processes of the gastrointestinal tract, the liver, and cystic fibrosis. This marker plays a crucial role in the diagnosis and monitoring of patients suffering from pancreatic cancer.
AFP (alfa-feto protein) is used to monitor pregnancy and the condition of the fetus, as well as to predict its eventual malformations. Increased values detect neural tube and ventral wall defects, and marker's reduced values detect chromosomal abnormalities (eg. Down syndrome). Additionally, AFP is a good indicator in monitoring the risk of apnea and respiratory problems in premature babies. It is commonly used for detection and monitoring of inflammatory processes and tumors of the liver and the germinal epithelium of the testicles and ovaries.
HCG is produced in the placenta shortly after the implantation of the embryo in the endometrium and is later excreted as an excess, first in the blood and then in the urine. Therefore, it is an exclusive indicator of pregnancy. Increased values detect gastrointestinal, urogenital and bronchial tumors, breast tumors and lymphomas. For patients with testicular tumors, HSG is examined in conjunction with AFP.
PSA is a specific tumor marker for prostate tissue in men. Elevated levels of this marker in the blood usually indicate a pathological condition of the prostate, such as prostatitis - gland inflammation caused by infection, benign enlargement, hyperplasia or malignant conditions. Commonly used for monitoring patient's condition after surgery and for investigating the effect of radiotherapy and hormone therapy. In cases when values are negative, it indicates that treatment and therapy are successful. Inflammation, physical damage or trauma to the prostate, can elevate the PSA concentrations values during different time periods.
HE4 has the highest sensitivity in detecting ovarian cancer, especially in the first stage of the disease, when it doesn't show any symptoms. Combined with CA 125, HE4, they give the best results in early diagnosis of ovarian cancer. HE4 values correlate the clinical response to therapy or recurrence of the disease in women suffering from ovarian cancer. Data obtained by the analysis of the HE4 tumor marker is confirmed by an X-ray, computer and magnetic imaging, and ultrasound examination findings. Therefore, HE4 is an early, subtle and important indicator for recurrence of ovarian cancer.
ROMA test - determining the risk of developing ovarian cancer
With the help of this subtle strategic tool, we can predict the danger of developing ovarian cancer. The measured values of the tumor markers CA 125 and HE4 play a significant role in making the right decision for further treatment of patients. The risk calculation effectiveness when using the ROMA algorithm is demonstrated in several clinical studies worldwide and can help doctors in classifying patients into groups with lower or higher risk for developing ovarian epithelial cancer.