Background: miRNAs regulate a multitude of cellular processes and their aberrant regulation is linked to human cancer. However, the role of miR-425-5p in lung cancer (LCa) is still largely unclear. Here, we explored the role of miR-425-5p during LCa tumorigenesis. Methods: Cell proliferation was evaluated by cell counting Kit-8 and colony formation assay. Western blot and realtime PCR were accordingly used to detect the relevant proteins, miRNA and gene expression. Luciferase reporter assays were used to illustrate the interaction between miR-425-5p and PTEN. Results: We demonstrate that miR-425-5p is overexpressed in LCa tissue and enhances the proliferative and colony formation capacity of the LCa cell lines A549 and NCI-H1299. Through predictive binding assays, PTEN was identified as a direct gene target and its exogenous expression inhibited the pro-cancer effects of miR-425-5p. Through its ability to down-regulate PTEN, miR-425-5p activated the PI3K/AKT axis. Conclusion: We conclude that miR-425-5p promotes LCa tumorigenesis through PTEN/PI3K/AKT signaling.

To evaluate the clinical significance of mRNA expression of cytokeratin 19 (CK19), epidermal growth factor receptor (EGFR) and lung-specific X protein (LUNX), a total of 42 patients who were diagnosed with non-small cell lung cancer (NSCLC) by pathology were studied retrospectively. The messenger RNA (mRNA) expression levels of CK19, EGFR and LUNX in the peripheral blood were analyzed using reverse transcription-polymerase chain reaction (RT-PCR). The expression of CK19 mRNA did not differ significantly according to the location, size, clinical stage or differentiation of the primary tumor (all P>0.05). However, there was a significant difference in the level of CK19 mRNA expression between squamous carcinoma and adenocarcinoma. The positive rates of EGFR mRNA in the patient and the healthy control groups were 69.0 and 12.5%, respectively, and were significantly different (P<0.05). The positive rates of LUNX mRNA in the two groups were 40.5 and 0%, respectively, and were significantly different (P<0.05). The results indicate that the mRNA expression of CK19, EGFR and LUNX in the peripheral blood is of significant clinical value for the diagnosis of micrometastasis and the prognosis of lung cancer.