Aims: Several microarray studies have reported microRNA expression signatures that classify cancer patients into different prognostic groups. No study has evaluated the association between microRNA expression patterns and gastric cancer prognosis. In this study, we developed a seven-microRNA signature that is closely associated with survival of patients with gastric cancer.
Patients and methods: MicroRNA expression profile was analyzed by real-time RT-PCR in 100 gastric cancer patients, which were randomly assigned to either the training set or the testing set. Cox proportional hazard regression and risk-score analysis were used to identify a stage-independent set of seven-microRNA signature in the training set that could classify patients with significantly different prognosis. This microRNA signature was further validated by the testing set and an independent cohort 60 patients.
Results: We have identified a seven-microRNA signature (miR-10b, miR-21, miR-223, miR-338, let-7a, miR-30a-5p, miR-126) for overall survival (P=0.0009) and relapse-free survival (P=0.0005) of gastric cancer patients. Multivariate analysis shown that the risk signature was an independent predictor of overall survival (hazard ratio=3.046; 95% CI, 1.246 to 7.445, P=0.015) and relapse-free survival (hazard ratio=3.337; 95% CI, 1.298 to 8.580, P=0.012). Furthermore, the predictive value of this seven-microRNA signature was validated in the testing set of 50 patients and an independent set of 60 patients.
Conclusion: Our seven-microRNA signature is closely associated with relapse-free and overall survival among patients with gastric cancer. The prognostic signature could be applicable to future decisions concerning treatment.