BACKGROUND

Previous studies indicated that dysregulated expression of nicotinamide -methyltransferase (NNMT) contributed to the tumor progression and predicted poor prognosis in various cancers. However, there was no exact conclusion on account of the contradictory results across studies.

METHODS

The relevant studies up to December 7, 2020 were searched in PubMed, Web of Science, and Embase. The association between NNMT expression and prognostic outcomes was explored, including overall survival (OS), disease-free survival (DFS), and clinicopathological features. The bioinformatics database was used to validate the findings.

RESULTS

Thirteen retrospective studies containing 2,591 patients with cancers were included in this analysis. High NNMT expression was significantly associated with shorter OS (hazard ratio [HR] = 2.01, 95% confidence interval [CI] = 1.42-2.86, and < 0.01) and DFS (HR = 1.59, 95% CI = 1.23-2.05, and < 0.01) compared to low NNMT expression in cancers. Compared to patients with low NNMT expression, patients with high NNMT expression tended to have worse tumor differentiation ( = 0.03), earlier lymph node metastasis ( = 0.01), earlier distant metastasis ( = 0.02), and more advanced clinical stage ( < 0.01).

CONCLUSION

High NNMT expression is an unfavorable factor of various cancers. NNMT is a promising indicator to predict the prognosis of various cancers and can serve as a potential therapeutic target in various cancers.