Diagnosis Of Early Stage Lung Cancer By Circulating Tumor DNA Gene Mutation

?Background?Lung cancer is one of the most common tumors in the world.Early diagnosis of lung cancer can improve the therapeutic effect and survival time of lung cancer.At present,screening for lung cancer from healthy people is usually performed by CT imaging with tumor marker examination.Imaging examination is convenient and rapid,non-invasive,and can be accepted by most people.The disadvantage is that it is difficult to display tiny lesions(diameter <1.5cm);tumor insufficient detection of markers is that the specificity is low,even in carcinoembryonic antigen(CEA),which is highly expressed in early lung cancer,because it can be produced not only in tumor cells but also from normal cells under stimulating factors such as inflammation.In addition,the current gold standard for the diagnosis of lung cancer is histopathological examination,some lesions are too small,the tumor location is deep,the tumor site is difficult to operate,the patient's own conditions and other factors have hindered the pathological material.Therefore,we need to explore further methods for large-scale screening and accurate diagnosis of early lung cancer.The discovery of circulating tumor DNA provides us with a new idea.Circulating tumor DNA(ctDNA)is secreted by tumor cells or tumor cells are necrotic,and apoptosis is released into the blood.The mutations present can represent tumor cells.Genetic variation.Many studies have demonstrated that ctDNA concentration determination before and after treatment can be used to evaluate the therapeutic effect and can be used for the evaluation of the efficacy of patients with advanced tumors.Because it is difficult to detect in the early stage of lung cancer,it is not used for the diagnosis of early lung cancer.With the development of second-generation gene sequencing technology,the sensitivity of detection of ctDNA mutation is improved,and ctDNA will be used for the diagnosis of early lung cancer.?Objective? The value of ctDNA in the diagnosis of early stage lung cancer is inconclusive.Based on the next-generation gene sequencing technology(NGS),this study selects the blood of early lung cancer and non-cancer patients,and detects the DNA mutation of circulating in peripheral blood.The sensitivity,specificity and accuracy of ctDNA diagnosis of early lung cancer are calculated.To determine the value of ctDNA in the diagnosis of early stage lung cancer.At the same time,this experiment will also detect the tumor marker CEA in the peripheral blood of the sample,calculate the sensitivity,specificity and accuracy of the CEA index and calculate the sensitivity,specificity and accuracy of the combination of the two test methods.To determine the value of ctDNA in the diagnosis of early stage lung cancer.?Experimental materials and methods?1.Case collection: From September 2017 to December 2017,12 patients with early stage lung cancer(IA,IB non-small cell lung cancer)were treated in Hospital.The staging of lung cancer was determined based on postoperative pathology or detailed imaging examination.From September 2017 to December 2017,5 patients with healthy or lung benign lesions were treated in hospital.2.Sample collection: venous blood was collected from patients on an empty stomach,10 ml of ctDNA was extracted,and 3 ml was used to detect CEA.3.DNA gene mutation assay: An NGS detection technique containing approximately 300 tumor-associated genes(including approximately 140 tumor driver genes and 160 tumor passenger genes from the TCGA database)was established to measure ctDNA variation in the samples.4.Data analysis:(1)Evaluation of ctDNA and CEA as indicators for screening and diagnosing early stage lung cancer,and calculating the sensitivity,specificity and accuracy of the two;(2)Compare the two screening methods and calculate the sensitivity,specificity and accuracy of the diagnosis of early lung cancer.?Experimental results?ctDNA mutation was detected in 10 patients with lung cancer,and ctDNA mutation was not detected in 5 normal patients.The specificity of early lung cancer was detected by ctDNA(100%).Sensitivity(83.33%)and accuracy(88.24%)were higher than CEA(80% specificity of CEA test,sensitivity 16.67%,accuracy 35.29%).The specificity,sensitivity and accuracy of ctDNA detection in early lung cancer were higher than the two.High(the specificity of the two test techniques is 80%,the sensitivity is 83.33%,and the accuracy is 35.29%).?Conclusion?ctDNA has a certain value in the diagnosis of early stage lung cancer,and the detection of ctDNA may be used for the diagnosis of early stage lung cancer.