Serum microRNA expression profiling revealing potential diagnostic biomarkers for lung adenocarcinoma

Background:Recent studies have demonstrated that microRNAs(miRNAs)in the blood circulation can serve as promising diagnostic markers for cancers.This four-stage study aimed at finding serum miRNAs as potential biomarkers for lung adenocarcinoma(LA)diagnosis.Methods:The study was carried out between 2016 and 2017.The Exiqon miRNA qPCR panel(3 LA vs.1 normal control[NC]pooled serum samples)was used for initial screening to acquire miRNA profiles.Thirty-five dysregulated miRNAs were further evaluated in the training(24 LA vs.24 NCs)and testing stages(110 LA vs.110 NCs)using quantitative real-time polymerase chain reaction assays.Results:Four serum miRNAs(miR-133a-3p,miR-584-5p,miR-10b-5p,and miR-221-3p)were significantly overexpressed in LA patients compared with NCs.The diagnostic value of the four-miRNA panel was validated by an external cohort(36 LA vs.36 NCs).The areas under the receiver operating characteristic curve of the four-miRNA panel in the training,testing,and external validation stages were 0.734,0.803,and 0.894 respectively.Meanwhile,the expression level of miR-221-3p was much higher in LA tumor samples than that in the adjacent normal tissues(19 LA vs.19 NCs).The expression level of miR-10b-5p was also elevated in the serum-derived exosomes samples(18 LA vs.18 NCs).The expression of miR-133a-3p,miR-584-5p,and miR-10b-5p was significantly elevated in LA patients with epidermal growth factor receptor mutation compared with NCs.Conclusion:The study established a four-miRNA signature in serum that could improve the diagnostic capability of LA.