Tumor-derived circulating exosomal miR-342-5p and miR-574-5p as promising diagnostic biomarkers for early-stage Lung Adenocarcinoma.

Lung cancer has been the leading cause of cancer morbidity and mortality in recent years. Most lung cancers are often asymptomatic until advanced or metastatic stage. Therefore, looking for the diagnostic biomarker for early-stage lung cancer is quite significant. Circulating exosomal microRNAs (miRNAs) have been reported to be the diagnostic and prognostic markers of various cancers. Here, we obtained circulating exosomal miRNA repertoires of 7 early-stage lung adenocarcinoma patients including pre-operation and post-operation (LA-pre and LA-post) and 7 heathy controls (HCs) by next generation sequence (NGS) and selected miR-342-5p, miR-574-5p and miR-222-3p to validate in ampliative samples by reverse transcription-quantitative PCR (RT-qPCR). Circulating exosomal miR-342-5p, miR-574-5p and miR-222-3p not only significantly elevated in LA patients (n = 56) compared with HCs (n = 40), but also significantly decreased after tumor resection when analyzed 51 paired pre- and post-operation samples. Furthermore, miR-342-5p and miR-574-5p, but not miR-222-3p, had a significantly elevated expression level in carcinoma tissue compared with adjacent non-cancerous tissue (n = 8). The receiver operating characteristic (ROC) curve showed the area under the curve (AUC) of combined miR-342-5p and miR-574-5p was 0.813 (95% CI: 0.7249 to 0.9009) with sensitivity and specificity of 80.0% and 73.2% respectively. In summary, circulating exosomal miR-342-5p and miR-574-5p have potential to serve as novel diagnostic biomarkers for early-stage LA.