Correlation between miR-138-5p expression and efficacy of platinum-based chemotherapy in advanced gastric cancer patients

BACKGROUND: We investigated the relationship between levels of microRNA (miR)-138-5p in plasma and tumor tissues from advanced gastric cancer patients, and the efficacy of first-line platinum-based chemotherapy. METHODS: MiR-138-5p expression was measured by qRT-PCR in cancerous tissues and plasma from 51 advanced gastric cancer patients, in paracancerous tissues and in plasma from healthy volunteers as control. All patients received first-line platinum-based chemotherapy. Correlations between miR-138-5p expression and the treatment efficacy, progression-free survival (PFS), and overall survival (OS) of first-line chemotherapy were evaluated. RESULTS: Significantly lower levels of miR-138-5p were detected in gastric cancer tissues compared with paracancerous tissues and in the plasma of patients compared with control subjects (both P<0.05). A positive correlation was detected between the treatment efficacy and miR-138-5p expression in both cancer tissues and plasma (P<0.05). Receiver-operating characteristic (ROC) curves were constructed to determine the optimal miR-138-5p cutoff value for predicting the efficacy of platinum-based chemotherapy. Patients with high miR-138-5p expression in either tissues (≥0.081) or plasma (≥0.047) had better treatment responses and longer PFS and OS than patients with low miR-138-5p expression (P<0.05), and multivariate analyses confirmed miR-138-5p expression as a promising prognostic biomarkers. CONCLUSIONS: Our study suggested that miR-138-5p expression in cancer tissues or plasma could be a useful predictive biomarker for the efficacy of platinum-based chemotherapy and prognoses in advanced gastric cancer patients.