A five-miRNA signature predicts survival in gastric cancer using bioinformatics analysis

Abnormal expression of miRNAs is critical for gastric cancer progression. Here, we aimed to identify the differential expression of miRNAs in normal and cancerous gastric tissues and build a nomogram for effectively predicting the survival of patients with gastric cancer. We used high-throughput miRNA data in The Cancer Genome Atlas (TCGA) database for this study. The discriminative capabilities and predictive accuracy of the nomogram depended on the calibration curve and concordance index (C-index), and comparisons were made between the nomogram and current gastric cancer staging systems. Data of 87 patients collected from TCGA as bootstrap resamples were used to validate the results. In total, 129 miRNAs were differential expressed, of which, prognostic function was associated with five miRNAs using Kaplan-Meier analysis. Functional enrichment analysis showed that the target genes of these miRNAs were involved in various cancer-related pathways. Age, metastasis, lymph node status, T stage and the five-miRNA signature were selected as independent survival variables, in the nomogram for primary cohort multivariate analysis. According to the survival probability calibration curve, the nomogram predictions were consistent with the actual observations. The survival predicting nomogram showed a C-index of 0.72 (95% CI, 0.64 to 0.78), which was significantly higher than the C-index of the American Joint Committee on Cancer (AJCC) seventh edition (0.60; P