Cancer markers are substances whose concentration and presence are associated with the development of cancer.
These are substances secreted into body fluids, such as blood or exudates, or found on the surfaces of cells, both neoplastic and nonneoplastic. The latter are detected by histopathological examination of tissues.
Tumour markers – division
- foetal and embryonic antigens – normally present in the foetus and appearing in tumour cells as a result of gene expression
- placental antigens – normally present in the blood of pregnant women and disappearing after delivery
- antigens secreted by typical cancer cells
- hormones produced excessively by tumours
Preparation for tumor marker testing
The test for tumour markers does not require any special preparation. Most often, markers circulating in the blood are determined; they are also detected in histopathological examinations of tissues obtained, for instance, by biopsy or during surgery.
Tumour markers – types
Fetal and germline antigens
Fetal cancer antigen (CEA) NORMA – 0.5-4 pg/1
Elevated levels of this marker are found in patients with colon, rectal, cervical cancer and liver metastases. Since the absence of this marker does not exclude the presence of cancer, it is used in the evaluation of the effectiveness of treatment rather than in diagnosis.
a – Fetoprotein (AFP) NORM 6-20 pg/1
It is present in higher amounts in the fetus and in newborns and pregnant women, later its concentration decreases with adolescence. Elevated concentrations are found in liver and testicular cancer; because increases in this antigen are found only in these cancers, it can be used for their diagnosis.
Chorionic gonadotropin NORMA up to 10j.m/l (in pregnancy up to 190j.m/l)
Physiologically, it is secreted by placental cells and, in patients with malignant tumors, by these tumors. Its level increases in: choriocarcinomas, testicular and ovarian monomas.
Antigens secreted by cancer cells
- CA 19-9 antigen – Secreted by cancer cells of the stomach, pancreas, colon and bile ducts.
- CA 125 antigen – Its levels are increased in ovarian cancer, but can also be elevated in pregnant women and in non-cancerous diseases.
- CA 15-3 Antigen – Detected in breast cancer cells and recognized as a marker for this cancer, with higher levels only appearing in the invasive phase, so it is now used more to evaluate the effectiveness of treatment.
- Prostate Prostate Antigen (PSA) – Is synthesized in the prostate gland, and its activity increases with prostate cancer.
- Tissue Prostate Antigen (TPS) – It is synthesized by the cells of many cancers, and it allows us to reflect the dynamics of cancer growth.
Indications for performing cancer markers
- evaluation of treatment effectiveness
- Diagnosis and detection of metastases
- evaluation of the effectiveness and accuracy of surgical removal of the tumor.
Tumor marker tests are performed at the patient’s expense or, if ordered by the doctor, for free. The result should be reported to the oncologist.