Increased expression of miR-181d is associated with poor prognosis and tumor progression of gastric cancer

Aberrant expression of miR-181d has been noted in multiple human cancers, but its role in gastric cancer (GC) remains unclear. The aim of this study was to investigate the expression, clinical significance and functional role of miR-181d in GC. We applied quantitative real-time polymerase chain reaction (qRT-PCR) to quantify the expression of miR-181d in 131 GC tissues, as well as in GC cell lines. The correlation of miR-181d expression with overall survival of GC patients was analyzed using the Kaplan-Meier survival method. Cox regression analysis was conducted to further determine the prognostic value of miR-181d in GC. Cellular functional experiments were carried out to calculate the effect that miR-181d had on GC behaviors. MiR-181d expression was significantly up-regulated in both GC tissues and cells (all P < 0.001), and correlated with TNM stage and lymph node metastasis (all P < 0.05). GC patients in the high miR-181d expression group had shorter survival time than those in the low miR-181d expression group (log-rank P < 0.001). Multivariate Cox regression analysis demonstrated that miR-181d expression and TNM stage were two independent prognostic markers for GC. Overexpression of miR-181d significantly promoted the NCI-N87 and MGC-803 cells proliferation, migration and invasion (all P < 0.05). MiR-181d serves a role as an oncogene in GC by promoting tumor progression. And miR-181d might be a novel predictive marker for the prognosis of GC patients.