Correlation Between Syncytin-1 And Non-small Cell Lung Cancer

BackgroundLung cancer seriously threatens the lives and health of the people,and is currently the world’s highest malignant tumor with the highest morbidity and mortality.In our country,lung cancer has become the leading cause of cancer death,and morbidity and mortality are still increasing.About 80%of patients with lung cancer classified by histopathology are non-small cell lung cancer（NSCLC）,of which late stage patients account for 40-50%of the total number of patients with non-small cell lung cancer.The commonly used treatments in the clinic are surgery,radiotherapy,chemotherapy and molecular targeted therapy.Syncytin-1 is a member of the human endogenous retroviral W gene family（HERVW1）,which is known to be highly expressed in human placenta tissue and plays an important role in placental development.Syncytin-1 is a functional fusion protein that mediates cytotrophoblast fusion to form a syncytiotrophoblast.In addition,studies in vitro have shown that syncytin-1 also has some non-fusion functions,such as cell proliferation,immunosuppression,cell cycle regulation and anti-apoptotic activity.It is known that high expression of syncytin-1 is found in a variety of human malignancies such as colorectal cancer,endometrial cancer,seminoma,ovarian cancer,breast cancer,leukemia and lymphoma,all of which are indicated that overexpression of syncytin-1 appears to be characteristic in human malignancies.The incidence of lung cancer is higher,but the 5-year survival rate is lower.The survival status of lung cancer patients after 5 years of follow-up surgery is further analyzed the relationship between the expression of syncytin-1 and the 5-year survival rate of patients,so as to provide experimental basis for improving the 5-year survival rate of patients with non-small cell lung cancer and seeking more scientific and reasonable treatment.In recent years,the role of epigenetics in the occurrence and development of tumors has become increasingly recognized.DNA methylation is a common epigenetic phenomenon,which refers to the action of DNA methyltransferases（DNMTs）,the process of covalently binding a methyl group provided by S-adenosylmethionine to the 5’ carbon position of CpG dinucleotide cytosine.The expression of syncytin-1 in non-small cell lung cancer and methylation status have not been reported at home and abroad.In this study,immunohistochemistry was used to detect the protein expression level of syncy tin-1 in non-small cell lung cancer and adjacent tissues.The 5’-LTR methylation of the syncytin-1 promoter region in non-small cell lung cancer and adjacent tissues was detected by MassARIRAY mass spectrometer EpiTYPER methylation method.To explore the relationship between the expression of syncytin-1 and non-small cell lung cancer and the relationship between methylation and gene expression,and provide a new tumor marker for the diagnosis,treatment and prognosis of lung cancer.Objective:To analyze the expression of syncytin-1 and methylation status in non-small cell lung cancer and adjacent tissues,and to explore the relationship between the expression of Syncytin-1 and the prognosis of patients and the pathogenesis of non-small cell lung cancer.Method:1.Immunohistochemistry was used to detect the expression of syncytin-1 in non-small cell lung cancer and adjacent tissues.The expression differences of 5-year survival group and 5-year death group were analyzed.Survival rate was calculated by Kaplan-Meier survival curve.Cox Proportional risk regression models were used to analyze risk factors for death.2.The MassARRAY EpiTYPER methylation method detects the 5’-LTR methylation status of the syncytin-1 promoter region in non-small cell lung cancer and adjacent tissues.Result:1.The expression intensity of syncytin-1 in non-small cell lung cancer tissues was significantly higher than that in adjacent tissues（P<0.01）.The expression intensity of syncytin-1 in the 5-year survival group was significantly lower than that in the 5-year death group（P<0.01）.2.The mean survival time of the high expression group was significantly lower than that of the low expression group（P<0.01）.The multivariate analysis of Cox proportional hazard regression model showed that clinical stage and the syncytin-1 positive cell rate were risk factors for non-small cell lung cancer death.3.The overall methylation rate of non-small cell lung cancer tissues was lower than that of adjacent tissues,but the difference was not statistically significant（P>0.05）.The methylation rate of CpG₂ non-small cell lung cancer tissues was lower than that of adjacent tissues（P<0.05）.Conclusion:1.Syncytin-1 is over-expressed in non-small cell lung cancer tissues,but not in adjacent tissues,which can be used as an indicator for prognosis,and high expression has a poor prognosis.2.The abnormally reduced methylation pattern of syncytin-1 in non-small cell lung cancer is involved in the occurrence of the disease,and the mechanism may be that the hypomethylation of the syncytin-1 promoter region promotes the expression of its gene.