The human body is a complex and sophisticated system. When there is a problem with this system, it will send out various signals to people, one of which is called the messenger of cancer. The appearance of the virus means that the human body may have tumors, but sometimes they are like the little boy who always shouts “the wolf is coming” and likes to joke with everyone. This kind of messenger is the tumor marker. What is the clinical application value of tumor markers, and what are the common tumor markers in the digestive system? Let’s take a look.
I. What are tumor markers?
Tumor markers (TM) refer to the synthesis and secretion of tumor cells’ gene expression during the occurrence and proliferation of malignant tumors, or the response of the body to tumor cells. A class of substances that are abnormally produced and/or elevated, reflecting the presence and growth of a tumor.
Second, what is the clinical value of tumor markers?
1.Screening and early detection of malignant tumors: Patients with high-risk factors such as family history of tumors have a relatively high incidence of tumors, and tumor markers should be carried out such as prostate-specific antigen PSA in men over 50 years of age with prostate adenoma.
2.Preliminary diagnosis of malignant tumors: Some tumor markers can be used for the diagnosis of malignant tumors, such as alpha-fetoprotein AFP for the diagnosis of primary liver cancer .
3. Prognosis : The prognosis of some tumors is related to the basal level of tumor markers before treatment. In general, the higher the basal level, the greater the likelihood of being at an advanced stage of cancer and the worse the prognosis.
4. Efficacy monitoring: The decrease in tumor marker concentration after surgery or after treatment is one of the signs of effective treatment. The tumor marker concentration does not decrease or decreases very little It indicates incomplete tumor resection or the presence of multiple tumors.
5. Monitoring of tumor recurrence: tumor markers can be reduced to normal after surgery, and tumor markers may increase again after tumor recurrence.
III. Common tumor markers of digestive system
1. Carcinoembryonic Antigen (CEA)
CEA is a polysaccharide protein complex mainly present in rectum, colon cancer tissues and embryonic intestinal mucosa. Such as colorectal cancer, pancreatic cancer, gastric cancer, esophageal cancer, gallbladder cancer, etc. are closely related to the incidence, but also closely related to the incidence of lung cancer, breast cancer, medullary thyroid cancer and other malignant tumors outside the digestive tract. When a patient presents with certain symptoms and the serum CEA concentration is 5- to 10-fold elevated, the presence of a tumor is highly suspected. The positive rates of CEA in malignant tumors were colon cancer (70%), gastric cancer (60%), pancreatic cancer (55%), lung cancer (50%), breast cancer (40%), ovarian cancer (30%), Uterine cancer (30%).
2. Alpha-Fetoprotein (AFP)
AFP is a macromolecular serum glycoprotein and an important indicator for the diagnosis of primary liver cancer. The serum level of normal people is less than 20ng/ml. When AFP continues to rise above 400-500ng/ml, the possibility of liver cancer should be highly suspected.
3. Carbohydrate Antigen 72-4 (CA72-4)
It is one of the best tumor markers for the diagnosis of gastric cancer. It has high specificity for gastric cancer, with a positive rate of 65-70%. In many patients with benign gastric diseases, its detection The rate is only 0.7%. The level of CA72-4 is also significantly correlated with the staging of gastric cancer. Generally, it increases in stages III-IV of gastric cancer. For gastric cancer patients with metastasis, the positive rate of CA72-4 is also much higher than that of non-metastatic patients. CA72-4 can also be used as an indicator for follow-up after treatment and for the judgment of recurrence and prognosis. The level of CA72-4 can be rapidly decreased to normal after surgery; in 70% of recurrence cases, the concentration of CA72-4 first increases.
4. Carbohydrate Antigen 19-9 (CA19-9)
It can be used as an auxiliary diagnostic index for malignant tumors such as pancreatic cancer and gallbladder cancer, and is of great significance for monitoring the changes and recurrence of the disease. Pancreatic cancer, gallbladder cancer, bile duct ampullary cancer, CA19-9 is significantly increased, especially the positive rate of advanced pancreatic cancer can reach 75%, which is an important auxiliary diagnostic indicator.
5. Carbohydrate antigen 50 (CA50)
It is also a broad-spectrum tumor marker. The positive rate of diagnosing rectal cancer is closely related to the stage of the disease. Duke A stage 19%-43%, B stage 30%-59%, 53%-73% of patients with C and D stages can be CA50 positive. At the same time, 80%-97% of pancreas, 58%-70% of cholangiocarcinoma, 41%-71% of esophageal cancer, 41%-71% of gastric cancer, and 14%-78% of liver cancer have elevated CA50.
6. Carbohydrate antigen 242 (CA242)
A mucin-related marker and a sialylated glycolipid antigen. When diagnosing pancreatic cancer, the sensitivity is 70%-80%, and the specificity is 90%, which can be used to screen pancreatic cancer at the initial diagnosis. The sensitivity and specificity for non-small cell lung cancer were 28.5% and 95.6%, respectively. The serum CA242 level in patients with lung squamous cell carcinoma was significantly lower than that in non-squamous carcinoma patients (lung adenocarcinoma and large cell lung cancer), which can be used for the differential diagnosis of lung cancer.
It should be noted that although the increase of tumor markers may mean that “the wolf is coming”, but sometimes it is not necessarily true, and it may also be other benign diseases, such as inflammation, benign Tumors, etc., or abnormal physiological states, such as menstruation, pregnancy, etc., so we should not be too nervous, because the wolf may not really come, but if your tumor marker is high, we must pay attention, Further diagnosis is made through other clinical examination methods, such as CT, magnetic resonance, gastrointestinal endoscopy, histological biopsy, etc., so as not to miss an important opportunity for diagnosis and treatment. (Text/Edited by Sang Suzhen/Xu Xiao)