BACKGROUND: The prognostic significance of miR-378 in cancers remains controversial. We carried out the meta-analysis to clarify the issue. METHODS: Related researches were obtained from PubMed, Web of Science and EMBASE. The search was conducted up until 10 September 2023. Hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to access the correlation between miR-378 and survival outcomes and clinicopathological features. RESULTS: 16 articles were included in the meta-analysis. The pooled analysis showed that low miR-378 expression predicted poor overall survival (OS) (HR: 1.73, 95% CI: 1.09-2.74). No significant difference was discovered between low miR-378 expression and disease-free survival/ recurrence-free survival (DFS/RFS) (HR: 1.43
95% CI: 0.79-2.59). Subgroup analysis revealed that the low miR-378 expression had better predictive value for CRC (HR: 2.97, 95% CI: 1.27-6.96), GC (HR: 2.12, 95% CI: 1.23-3.67) and glioma (HR: 3.87, 95% CI: 1.52-9.81). In addition, low miR-378 expression had positive correlation with lymph node metastasis (yes vs. no)(OR: 2.42, 95% CI: 1.55-2.87) and distant metastasis (yes vs. no) (OR: 1.26, 95% CI: 1.04-2.35). CONCLUSION: MiR-378 could be an efficient prognostic biomarker in cancers.