Expression level and clinical significance of serum exosomal miR-744-5p in non-small cell lung cancer

Objective To analysis the expression level and clinical value of serum exosomal miR-744-5p in non-small cell lung cancer (NSCLC). Methods Retrospective study. A total of 183 subjects, including 92 NSCLC patients and 91 healthy controls, were recruited from Nanfang Hospital Affiliated to Southern Medical University from November 2016 to February 2018. Exosomes were extracted using ExoQuick and the total RNA was extracted from the exosomes.The expression level of serum exosomal miR-744-5p was assessed by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). The diagnostic efficiency of exosomal miR-744-5p was evaluated by receiver operating characteristic (ROC) curve. Results The qRT-PCR results revealed that the expression level of serum exosomal miR-744-5p in patients with NSCLC (0.012 2±0.019 7) was significantly lower than that in the healthy control (0.093 6±0.081 9), and the difference was statistically significant (U=553.5, P<0.001). Furthermore, the level of miR-744-5p in patients with early stage (stage Ⅰ and Ⅱ) lung cancer(0.011 7±0.013 9) was significantly different, when compared to healthy controls (U=72.5, P<0.001). The exosomal level of miR-744-5p in samples (0.010 6±0.020 3) was lower than that in squamous cell carcinoma serum (0.017 3±0.017 8) , and the difference was statistically significant (U=394.5, P<0.001). The ROC curve revealed that miR-744-5p expression can be a significant biomarker to discriminate between normal and NSCLC cases, with an area under the ROC curve of 0.933 9 (95%CI=0.899 6-0.968 1, P<0.000 1). MiR-744-5p can effectively diagnose early stage NSCLC, with an area under the ROC curve of 0.943 1 (95%CI=0.883 7-1.000 0, P<0.000 1). Conclusion The serum exosomal miR-744-5p could serve as a non-invasive biomarker for the diagnosis of NSCLC, but further comparative research and expanded verification are needed. Key words: Carcinoma, non-small-cell lung; Exosomes; microRNAs; Biomarkers, tumor