| Esophageal cancer(EC)is one of the most common malignant tumors of digestive tract in China.Its early clinical symptoms are not obvious.Most of the cases were diagnosed in the middle and advanced stages.It is easy to metastasize and relapse.The 5-year survival rate is only about 30%.Early diagnosis and monitoring of recurrence and metastasis are particularly important to improve the quality of life of patients with esophageal cancer.At present,the diagnosis of esophageal cancer is mainly based on X-ray barium meal radiography,computed tomography or nuclear magnetic resonance imaging(CT/MRI),endoscopic ultrasonography and PET/CT.X-ray barium meal radiography has some limitations in judging the depth of invasion of early esophageal cancer.CT/MRI is difficult to detect tumors less than 2 mm.Ultrasound endoscopy is not suitable for patients with esophageal stricture obstruction and poor physical tolerance.The real-time monitoring of tumors can not be achieved by repetitive operation.PET/CT is expensive,and there are some false positive and false negative results.Therefore,it is very important to find a convenient,accurate and monitoring technology for malignant tumor cells."Liquid biopsy" refers to a blood-based non-invasive body fluid test,which has the characteristics of non-invasiveness,convenience and high repeatability.It has broad clinical application prospects.The main detectors are circulating tumor cells(CTCs)and circulating tumor DNA(CTDNA).CTCs refer to the detachment from the primary or metastatic tumors into the body.Tumor cells in the blood circulation system,CT DNA is a kind of free DNA fragment which comes from DNA fragments of necrotic or apoptotic cancer cells,DNA fragments secreted by proliferating active cancer cells or CTCs and is released into peripheral blood circulation by tumor cells.This article reviews the biological characteristics,enrichment and detection methods of CTCs and CT DNA,and their research progress and case analysis in diagnosis,treatment and prognosis monitoring of EC. |
