Carcinoembryonic antigen (CEA) test
Indications for carcinoembryonic antigen (CEA) test:
- Monitoring the course of disease and effectiveness of colon cancer, breast cancer and lung cancer therapy
- Diagnosis of C-cell thyroid carcinoma
- Screening of risk groups, monitoring of disease development and the effectiveness of therapy in patients with colorectal carcinoma
Carcinoembryonic antigen (CEA) is a glycoprotein with a molecular weight of 175-200 kDa. CEA tumor marker during electrophoresis migrates in the area of mobility of β-globulins.
One of the most significant features of the molecular structure of carcinoembryonic antigen (CEA) is high (60%) carbohydrate content, which determines the high heterogeneity of the physico-chemical properties. In the molecule of CEA tumor marker identified 6 different antigenic determinants.
Carcinoembryonic antigen (CEA) is a tumor-embryonal antigen produced in the tissues of the digestive tract of the embryo and fetus and is determined in the blood serum of the fetus. In the blood of pregnant women, this glycoprotein was not detected.
After the baby is born its synthesis is suppressed. Therefore, in the serum of healthy adults it is virtually nonexistent, as well as in other biological fluids. In very small quantities carcinoembryonic antigen (CEA) is found only in some adult tissues, such as intestinal, liver, and pancreas.
During the development of tumors the concentration of carcinoembryonic antigen (CEA) in serum is improved and accurately reflects the state of the malignant process. The high concentration of CEA tumor marker are determined in colorectal carcinomas.
Carcinoembryonic antigen (CEA) normal range usually does not exceed 3 kg/ml. The level of carcinoembryonic antigen (CEA) is affected by smoking, alcohol consumption. For non-smokers the norm is 2.5-5 ng/ml. Normal range for healthy smokers is 7-10 ng/ml.
In digestive tract and respiratory tract carcinomas in 50-90% of patients, levels of CEA in the blood is above normal, the same is observed in 30-50% of patients with breast carcinomas, head and neck carcinomas, as well as in 25% of patients with malignant tumors of connective tissue origin.
If untreated malignant tumors the level of CEA tumor marker increases constantly.
In 20-50% of patients with somatic diseases (cirrhosis of the liver, chronic hepatitis, pancreatitis, ulcerative colitis, Crohn's disease, pneumonia, bronchitis, tuberculosis, emphysema, cystic fibrosis, autoimmune diseases) detected elevated levels of carcinoembryonic antigen (CEA) in serum. However, in these cases, the level of CEA tumor marker is rarely above 10 ng/ml, and after clinical improvement is generally normalized.