Application Value Of Serum Exosomes TMEM88 Protein In Liquid Biopsy For Diagnosis And Prognosis Of Non-small Cell Lung Cancer

Background:According to the National Cancer Registry in 2015,non-small cell lung cancer(NSCLC)is one of the most common malignancies in China,and it is also the leading cause of cancer-related death.Statistics show that: The 5-year survival rate of the patients with early NSCLC after surgery was 86%.However,lung cancer is often difficult to diagnose early.Most patients with NSCLC are at a late stage of diagnosis,whose 5-year survival rate is less than 10%.The use of bronchoscopy,mediastinoscopy,or thoracic biopsy is the most reliable method for the diagnosis of NSCLC,but these operations are not suitable for census of diseases and are less suitable for continuous monitoring.Therefore,exploring new markers for early diagnosis of NSCLC is critical for patients to improve survival time.Exosomes are small vesicles with lipid bilayer structure secreted by cells,which can be detected in the blood,urine,pleural effusion and other body fluids containing protein,lipid,nucleic acid,metabolite,and reflecting the physiological and pathological status of the source cells.They have great potential for cancer-related noninvasive liquid biopsy studies.TMEM88 is a member of the transmembrane protein family,which plays a key role in regulating human embryonic stem cell differentiation and embryonic development.The current study shows that TMEM88 protein is highly expressed in a variety of tumors.TMEM88 protein can regulate the proliferation,migration and invasion of tumor cells,which is closely related to the occurrence,development and prognosis of tumor.Therefore,the tumor-derived exosomal TMEM88 protein is expected to become a new marker for noninvasive diagnosis and screening of tumors.Objective:Comparing the level of TMEM88 protein among the untreated group,the surgical group,the benign disease group and the healthy control group.Comparing the level of TMEM88 protein of the untreated group in the exosomes and the corresponding paraffin tissues.Exploring the application value of TMEM88 protein in the early diagnosis and prognosis of liquid biopsy of NSCLC.Methods:52 cases were enrolled in the study,including 22 untreated cases,10 casess after surgery,10 benign disease and 10 age matched healthy controls.Serum exosomes were isolated by differential ultracentrifugation.Use transmission electron microscopy to identify the characteristics of exosome.Identify the exosome surface marker protein TSG101 and CD63 by Western blot.Identify the expression of TMEM88 from the exosomes by Western blot.The gray scale of the protein bands was calculated by Image J software.The expression level of TMEM88 protein in paraffin tissue was detected by immunohistochemistry,and the expression level of TMEM88 protein was calculated by Image-Pro Plus image analysis software.Comparing the level of TMEM88 amomg the untreated group(Untreat),Surgery group,benign disease group(Benign)and healthy group(Health).Comparing the consistency of TMEM88 protein expressed in the exosomes and the tumor tissues of the untreated group.Results:1.The circular or oval double-layer lipid membrane vesicles with diameter of 30-120 nm were detected in the serum.Western blot showed that TSG101 and D63 were expressed,so we identified them as exosomes.2.The expression of TMEM88 in untreated group was significantly higher than that in benign disease group and healthy group(p <0.05),which may be related to the occurrence of non-small cell lung cancer.The expression of TMEM88 in operation group was significantly lower than that in untreated group(P <0.05),which may be related to tumor burden elimination.(P <0.05).3.The expression of TMEM88 in the serum of the lymph node positive group was higher than that in the negative group(P <0.05).The expression of TMEM88 in the group of vascular thrombus positive was higher than that in the negative group.The expression of TMEM88 was correlated with staging(p <0.05).4.The expression of TMEM88 protein in the serum exosome of untreated group was correlated with the tumor tissue(p <0.05).Conclusion:1.The expression of TMEM88 protein was significantly higher in NSCLC patients.2.The expression level of TMEM88 protein in serum of patients with NSCLC was down-regulated after operation.3.The expression of TMEM88 protein in serum of patients with NSCLC was correlated with high stage,lymph node metastasis and vascular thrombus.4.The expression of TMEM88 protein in the serum of the untreated group was consistent with the tumor tissue.