The Clinical Significance and Prognostic Value of ALDH1 Expression in Non-small Cell Lung Cancer: A Systematic Review and Meta-analysis

Background: The results of the association between aldehyde dehydrogenase 1 (ALDH1) expression and prognosis of non-small cell lung cancer (NSCLC) are contradictory. We conducted this meta-analysis to investigate the clinical significance and prognostic value of ALDH1 in NSCLC. Methods: The databases PubMed, Web of Science, EMBASE, the Cochrane Library, Wanfang, and CNKI were systematically queried to identify eligible studies. The retrieval time was from database establishment to August 2023. We evaluated the correlation between ALDH1 expression and clinical features of NSCLC by employing odds ratios (ORs) and 95% confidence intervals (95% CIs). In addition, we used hazard ratios (HRs) and 95% CIs to evaluate the role of ALDH1 expression in the prognosis of NSCLC. Results: Our study included 21 literatures involving 2721 patients. The expression of ALDH1 in NSCLC was higher than that in normal tissues (OR = 6.04, 95% CI: 1.25-29.27, P = 0.026). The expression of ALDH1 was related to TNM stage (OR = 1.81, 95% CI: 1.06-3.09, P = 0.029), tumor grade (OR = 0.29, 95% CI: 0.17-0.48, P < 0.0001), lymph node metastasis (OR = 2.60, 95% CI: 1.52-4.45, P = 0001) and histological subtype (OR = 0.67, 95% CI: 0.52-0.86, P = 0.002). In patients with NSCLC, we found that the over-expression of ALDH1 was significantly associated with poor overall survival (OS) (HR = 1.44, 95% CI: 1.15-1.81, P = 0.002) and disease-free survival (DFS) (HR = 1.74, 95% CI: 1.45-2.10, P < 0.0001). Conclusion: The expression of ALDH1 is closely associated with the clinicopathologic characteristics and prognosis of NSCLC. ALDH1 may serve as a valuable clinical assessment tool and prognostic predictor in NSCLC.