Methylation Site Of MiR-191 Promoter In Non-small Cell Lung Cancer And Clinical Characteristics Analysis

OBJECTIVE:The possibility of methylation status of the miR-191promoter and methylation status of the mi R-191 promoter was examined as an indicator for the prognosis of Non-small cell lung cancer(NSCLC).METHODS:The methylation status of the miR-191 promoter region was predicted by a bioinformatics website.Download methylation data(Illumina Human Methylation 450 lvl-3)and corresponding clinical information from TCGA(The Cancer Genome Atlas)of 484 LUAD(lung adenocarcinoma)patients and 397 LUSC(lung squamous cell carcinoma)patients.Analyze whether the methylation status of the miR-191 promoter region is different,and compare the difference in age,gender,TNM stage,and prognosis between the hypomethylated and hypermethylated groups.128 postoperative NSCLC tissues and corresponding paracancerous tissues were collected,and the most specific methylation sites were selected to design the primers.Methylation-specific PCR(MSP)was used to detect the methylation level of mi R-191 promoter in lung cancer and paracancerous tissues.The relationship between the methylation level of miR-191 promoter and sex,age,differentiation,TNM staging,tissue type and prognosis was analyzed.Results:Bioinformatics results showed the presence of CpG islands in the miR-191 promoter region.Analysis of the TCGA database showed that the methylation of cg17217654 in the promoter region of mi R-191 was significantly lower in LUAD and LUSC than in normal lung tissue(P<0.001).Moreover,the methylation level of miR-191 promoter was correlated with the TNM stage of patients,and the methylation level of patients with a later stage was lower(P=0.025).Survival analysis showed that the overall survival of patients with low methylation levels of the miR-191 promoter in the LUAD and LUSC groups was shorter(P=0.0116).According to the primers designed at cg17217654 site,specific bands could be amplified.After extending the sample to 128 cases,methylation was detected in 57 of 128 lung cancer specimens,the methylation rate was 44.5%,Hypermethylation occurred in 105 of 128 normal lung specimens,and the methylation rate was 82.0%.The methylation rate of mi R-191 promoter was statistically analyzed between lung cancer tissues and normal lung tissues.The difference between groups was statistically significant(χ~2=38.733,P=0.000),and the methylation level was related to the degree of histological differentiation and TNM staging of patients(P<0.05),but was not significantly related to gender,age,and tissue type.Sex(P>0.05),survival analysis showed that patients with miR-191 promoter hypomethylation had a shorter overall survival(P=0.0139).Conclusion:Methylation of the miR-191 promoter plays a crucial role in the development of lung cancer.Among them,the methylation level of miR-191promoter region in lung cancer tissues was significantly lower than that in paracancerous tissues,and patients with low methylation levels had a later TNM staging and shorter overall survival.MSP results showed that the methylation rate of lung cancer tissue was significantly lower than that of the paracancerous tissue.The degree of tissue differentiation of unmethylated patients was lower and TNM staging was later.Patients in the unmethylated group had a shorter overall survival than those in the methylated group.In this study,a specific methylation site was successfully screened and verified,and methylation of this site was associated with the TNM stage and prognosis of the patient.These results indicate that abnormal methylation of the miR-191 promoter may be involved in the development of lung cancer.