Introduction and objective:
Non-small Cell Lung Cancer (NSCLC) destroys lung tissue, causing respiratory failure and even multi-system damage. There is an urgent clinical need for targeted drugs for the early diagnosis of NSCLC. miR-6838-5p is aberrantly expressed in a variety of cancers but its role in NSCLC is unclear. The aim of the study is to evaluate the diagnostic and prognostic value of miR-6838-5p in NSCLC.

Material and methods:
The study included 87 patients with NSCLC and 87 healthy individuals as control. Human normal lung epithelial cells (16HBE) and lung cancer cell lines (A-549/H1299/H1944/NCI-H460/NCI-H1975) were cultured for relevant testing. RT-qPCR was employed to assay miR-6838-5p and insulin-like growth factor 1 receptor (IGF1R) levels. Receiver operating characteristic (ROC) curves and Kaplan-Meier curves were used to assess clinical value. Cell counting kit-8 (CCK-8), flow cytometry, and transwell assays were employed to examine the biological functions of lung cancer cells. IGF1R was identified as downstream of miR-6838-5p by luciferase reporter gene assay.

Results:
miR-6838-5p level was clearly down-regulated in NSCLC patients. miR-6838-5p demonstrates significant diagnostic value for NSCLC, and patients with high expression of miR-6838-5p exhibit improved prognostic survival rates. And it is closely associated with NSCLC proliferation and migration. IGF1R is a target of miR-6838-5p and up-regulated in lung cancer cell lines. Furthermore, up-regulation of IGF1R partially restored the inhibitory effects of miR-6838-5p over-expression on proliferation and migration, as well as the promotion of apoptosis.

Conclusions:
miR-6838-5p is downregulated in NSCLC and may suppress its malignant progression by inhibiting IGF1R levels. This may provide an effective target for clinical diagnosis and prognosis.