The Expression And Clinical Significance Of Long Non-coding RNA AFAP1-AS1 In Non-small Cell Lung Cancer

Background The morbidity and mortality of lung cancer in the world within the scope of rapid growth.Up to now,lung cancer has become the main cause of cancer death worldwide.In China,the incidence of lung cancer rapidly rising year by year.In all of the Lung Cancer,non-small Cell Lung Cancer(Non-small Cell Lung Cancer,NSCLC)accounts for 75-80%.A growing number of studies have shown that non-coding RNA plays an important role in tumor occurrence and metastasis.Among them,the long non-coding RNA is involved in many biological processes of tumor.For example lncRNA HOTAIR,MALAT1,CCAT2 is closely related to occurrence,invasion and metastasis of lung cancer and prognosis,which can take as the diagnostic and prognosis biomarkers of lung cancer.In the present study,a novel lncRNA,actin filament associated protein 1 antisense RNA 1(AFAP1-AS1),was investigated,which is highly expressed in non-small cell lung cancer(NSCLC).The aim of this research was to detect the expression level of AFAP1-AS1 in the tumor tissues and adjacent normal lung tissues of NSCLC patients,and explore its correlation with the prognosis of patients.Methods In situ hybridization and reverse transcription-quantitative polymerase chain reaction were performed to detect AFAP1-AS1 expression in frozen tissues and tissue microarrays,respectively.TMA cohort of 74 NSCLC patients(55 males and 19females)with a median age of 61.1 years,and an PCR cohort of 52 NSCLC patients(30 males and 22 females)with a median age of 59.0 years were included in the present study.TMA cohort was structured in 2015 and the PCR cohort was accomplished in 2016.These samples were taken from Cancer Institute of Jiangsu.Results The TMA results revealed that the expression level of AFAP1-AS1 was significantly increased in tumor tissues,compared with the paired non-cancerous tissues.It was also determined that the AFAP1-AS1 expression level was higher in patients with lymph node metastasis than those without lymph node metastasis(P=0.007).Kaplan-Meier analysis was conducted to evaluate the overall survival ofpatients with NSCLC and different expression levels of AFAP1-AS1,and the results indicated that patients with high AFAP1-AS1 expression had a reduced survival time,compared with those with low AFAP1-AS1 expression(P=0.011).Cox regression analysis was also performed to analyze the prognostic value of lncRNA AFAP1-AS1.The obtained data demonstrated that lncRNA AFAP1-AS1 was an unfavorable prognostic biomarker for NSCLC(HR: 3.12,95%CI(1.05-9.25),P=0.040).The qRT-PCR results revealed that AFAP1-AS1 was over-expressed in NSCLC,with an mean up-regulation of 8.65-fold(P=0.040).Additionally,over-expression of AFAP1-AS1 was positively correlated with tissue differentiation(P=0.041)and lymph node metastasis(P=0.014).Conclusion In conclusion,it was demonstrated that lncRNA AFAP1-AS1 is over-expressed in NSCLC and an unfavorable biomarker for patients with NSCLC.