Elevated serum alpha-fetoprotein

Introduction A type of fetal protein (alpha-fetoprotein, AFP) is an important component of fetal serum during embryonic period, and the serum content per ml is as high as 1 mg or more. However, in adult serum, its content is only a nanogram level. However, after adults with primary liver cancer or teratomas, the level of serum AFP will increase again, so AFP is a carcinoembryonic anti-protein. As early as the 1950s, scholars found AFP in fetal serum. In the 1960s, alpha-fetoprotein was also found in the serum of human or animal with primary liver cancer. Later, this discovery was gradually used for clinical diagnosis of liver cancer. In addition to embryonal cancer, AFP is highly specific for the diagnosis of liver cancer.

Cause

The cause of elevated serum alpha-fetoprotein

In clinical acute viral hepatitis, chronic active hepatitis, liver fibrosis and hepatic lobular hyperplasia, patients with elevated serum AFP levels may be associated with liver regeneration.

In primary liver cancer, the synthetic site of AFP is a liver cancer cell, which is synthesized on the ribosome of the rough endoplasmic reticulum of liver cancer cells. However, not all AFPs in liver cancer cells are positive. It can be explained that 1AFP is synthesized only in a certain period of cell proliferation. Hepatoma cells not in this period do not synthesize AFP, so cell AFP is negative; 2 there is synthetic and non-synthetic AFP. There are two kinds of cancer cells, but there is no obvious difference in morphology between the two cancer cells.

The synthesis of embryonic carcinoma AFP: embryonic cancer such as testis, ovary, appendix and posterior peritoneal malignant teratoma, etc., the serum AFP content increased. The reason is that these embryonic cancers contain yolk sac components, and the yolk sac can synthesize AFP.

AFP synthesis in other tumors, gastric cancer, esophageal cancer, pancreatic cancer, gallbladder cancer, lung cancer, breast cancer can also produce AFP. Among them, gastric cancer is the most common, especially those with liver metastasis.

an examination

Related inspection

Serum alpha-fetoprotein (AFP) blood test

Examination of elevated serum alpha-fetoprotein

There are several methods commonly used to detect AFP:

(1) Agar bidirectional diffusion method (abbreviated as diffusion method, AGD): The threshold of this method is generally 3000 g, that is, only the serum AFP concentration reaches or exceeds this threshold, and a positive result can be detected, otherwise it is negative. The method has high specificity for the diagnosis of liver cancer. Non-cancerous liver disease, pregnancy and metastatic cancer rarely reach such a high concentration, so AFP is negative, but its sensitivity is poor, and it is prone to false negative, resulting in missed diagnosis.

(2) Convective immunoelectrophoresis (referred to as convection method, CIEP): This method has the characteristics of simple, rapid (2 hours to complete detection) and reliable (good specificity). It can be carried out under normal electrophoresis conditions. The principle is: two rows of holes are arranged on the agar plate, one AFP antibody is discharged, and the serum to be tested is discharged. When electrophoresis, the white precipitate line is positive when the antigen-antibody moves meet. The threshold (sensitivity) is 300 to 500 g/L. Pregnancy and non-cancerous liver diseases such as hepatitis rarely reach this level, so this method has a high specificity for the diagnosis of liver cancer. The disadvantage is that the sensitivity is slightly worse, the positive rate is about 80%, it can not be quantified, and false negatives can occur.

(3) Reverse indirect hemagglutination method (referred to as blood coagulation method, RPHA): This method has the advantages of fastness, high sensitivity and simplicity. The threshold (1; 10, ++) is about 50 g/L, although the sensitivity is better. High, the positive rate is about 90%, but there are often positive results in pregnancy and non-cancerous liver disease. However, this method is simple and easy to use and can be used for preliminary screening of liver cancer screening.

(4) Radioactive rocket electrophoresis (Racket Method, RRIA): This method can calculate the content of AFP. The threshold value depends on the standard sample, generally 20-30 g/L, and the positive rate is about 90%. This method is simple, economical and practical. It does not require special equipment and equipment, and can meet the requirements of clinical use, but it is not as accurate as the radioimmunoassay.

(5) Radioimmunoassay (radioimmunoassay, RIA): This method can quantitatively measure the content of AFP, and has high sensitivity. It can detect AFP of 5-10 g/L, and the positive rate is above 90%. Can be used to: 1 found early liver cancer; 2 for the diagnosis of liver cancer with only low concentration of AFP; 8 predict the condition, understand whether the operation is thorough, evaluate the effect of treatment, predict recurrence. The method is a highly sensitive method, and a positive result can be detected in pregnancy and non-cancerous liver diseases, and attention should be paid to identification.

AFP detection is relatively specific for the diagnosis of liver cancer. Most scholars believe that AFP is positive by convection method, or the diagnosis of liver cancer can be considered when the AFP is above 400g/L. In December 1977, the National Conference on Prevention and Treatment of Liver Cancer Prevention and Control was drafted: "If there is no evidence of liver cancer, AFP convection immunoelectrophoresis is positive or quantitative more than 500g / L for more than 1 month, and can exclude pregnancy, active liver disease, gonad embryo A tumor or the like can be diagnosed as hepatocellular carcinoma.

Differential diagnosis

Symptoms of elevated serum alpha-fetoprotein

Serum testosterone concentration is significantly increased: the normal menstrual cycle follicular phase, the average serum testosterone concentration is 0.43ng / ml, the high limit is 0.68ng / ml, such as more than 0.7ng / m1 (equal to 2.44nmol / L), known as high Testosteroneemia, or hyperandrogenism. Ovarian, adrenal cortex, etc. can synthesize cholesterol from acetic acid, or absorb cholesterol from the blood as a matrix, synthesize steroid hormones, and secrete into the blood circulation. The androgens in the blood circulation are mainly DHEAS, DHEA, androstenedione (4A), testosterone (T) and dihydrotestosterone (DHT). High testosteroneemia, which is formed by the high levels of these hormones, especially testosterone in the blood.

Serum immunoglobulin can be elevated: immunoglobulin, which refers to animal protein with antibody activity. It is mainly found in plasma and is also found in other body fluids, tissues and some secretions. Serum immunoglobulins (Ig) include: IgG, IgA, IgM, IgD, IgE. The normal range is IgG 7.6 to 16.6 g/L; IgA 0.71 to 3.35 g/L; IgM 0.48 to 2.12 g/L; IgD 0.01 to 0.04 g/L; IgE 0.001 to 0.009 g/L. Common causes are: 1. Chronic liver disease: including autoimmune chronic hepatitis, chronic active hepatitis, cirrhosis, chronic alcoholic liver disease, primary biliary cirrhosis. The degree of globulin increase is related to the severity of liver disease. 2. Autoimmune diseases. 3, chronic inflammation and chronic infections: such as tuberculosis, malaria and so on. 4, M globulinemia: such as multiple myeloma, lymphoma, primary macroglobulinemia.

Increased serum calcitonin levels: Serum calcitonin is a hormone secreted by thyroid follicular cells. When it is elevated for some reason, it can increase the amount of calcium excreted by the kidneys and lower the blood calcium concentration. Calcitonin is a thirty-two peptide containing a disulfide bond and has a molecular weight of 3,400. Normal human serum has a calcitonin concentration of 10-20 ng/L and a plasma half-life of less than 1 h, which is mainly degraded and excreted in the kidney. The main role of calcitonin is to lower blood calcium and blood phosphorus. The main target organ is bone, which also has a certain effect on the kidney.

Elevated serum TG levels: Serum triglycerides (TG) are one of the components of blood esters. Triglycerides are in a dynamic equilibrium in the human body. The content of blood esters can vary with changes in the diet and varies widely. In addition, its content increases with age, especially in middle-aged and elderly people whose body weight exceeds the standard.

AFP detection is relatively specific for the diagnosis of liver cancer. Most scholars believe that AFP is positive by convection method, or the diagnosis of liver cancer can be considered when the AFP is above 400g/L. In December 1977, the National Conference on Prevention and Treatment of Liver Cancer Prevention and Control was drafted: "If there is no evidence of liver cancer, AFP convection immunoelectrophoresis is positive or quantitative more than 500g / L for more than 1 month, and can exclude pregnancy, active liver disease, gonad embryo A tumor or the like can be diagnosed as hepatocellular carcinoma.

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