Expression of miRNA-25 in young and old lung adenocarcinoma

Background: An appropriate personalized molecular testing ensures the most efficacious treatment in lung cancer. It is still controversial whether younger lung adenocarcinoma (LUAD) patients have different molecular features compared with their older counterparts. MicroRNAs have been involved in lung cancer and their altered expression has been suggested as a potential biomarker in the pathogenesis, diagnosis, prognosis, and therapy of LUAD. Materials and Methods: To analyze putative differences in miR-25 expression between young (with age ≤50 years) and old adenocarcinoma patients, we quantified miR-25 levels with NanoString technology in 88 LUAD specimens. We further investigated a cohort of 309 LUAD patients from the cancer genome atlas (TCGA) database to test our hypothesis. Results: miR-25 expression was upregulated in young LUAD patients in comparison to the older ones (P = 0.03) in our series. The analysis of public database TCGA confirmed our results, which miR-25 differentially expressed in the two aged groups (P = 0.0009). Moreover, a consequential pairing of miR-25 with a target region in phosphatase and tensin homolog (PTEN) 3' untranslated region (UTR) and actually low PTEN expression seemed to be associated with high miR-25 (P = 0.001) in young patients. Conclusions: The interaction of miR-25 and PTEN in young LUAD may define a subgroup of patients, highlighting the concept of molecular testing in different age subtypes.