Identification of exosomal microRNA panel as diagnostic and prognostic biomarker for small cell lung cancer [miRNAseq_exosome]

Small cell lung cancer (SCLC) has an exceptionally poor prognosis; as most of the cases are initially diagnosed as extensive disease with hematogenous metastasis. Therefore, the early diagnosis of SCLC is very important and may improve its prognosis. To investigate the feasibility of early diagnosis of SCLC, we examined exosomal microRNAs (miRNAs) present in serum obtained from patients with SCLC. Exosomes were isolated in serum from patients with SCLC and healthy individuals and were characterized using particle size and protein markers. Additionally, miRNA array was performed to define SCLC-specific exosomal miRNAs. The miRNAs identified in the miRNA array results were validated using a large cohort. Gene ontology analysis has revealed that a panel of miRNAs are linked to various oncogene pathways and nervous system development. Changes in mRNA expression when target miRNAs were introduced into BEAS2B cells strongly indicated the presence of lung diseases, including lung cancer. Additionally, miRNA panels are significantly associated with poor prognosis. In conclusion, our study identified SCLC-specific exosomal miRNAs, and the miRNAs panel may serve as a diagnostic and prognostic marker for SCLC. Comparative gene expression profiling analysis of RNA-seq data for serum-derived exosomal miRNAs from 5 patients with SCLC and 5 controls with lung nodules.