Apolipoprotein A-1 as a Potential Biomarker for Solid Tumors: A Systematic Review and Meta-Analysis

Background: The diagnostic value of apolipoprotein A-I (ApoA-I) as a marker of different malignancies has been reported in several investigations; however, the results have been contradictory. The current meta-analysis examined the association between ApoA-I levels and human malignancies. Methods: We reviewed the databases and retrieved papers for analysis until November 1^st, 2021. Random-effects meta-analysis was performed to construct the pooled diagnostic parameters. To find the causes of heterogeneity, we utilized Spearman threshold effect analysis and subgroup analysis. The I² and Chi-square tests were used to examine the heterogeneity. Moreover, subgroup analyses were performed based on sample type (serum/urine) and geographical region of study. Finally, publication bias was explored using Begg's and Egger’s tests. Results: A total of 11 articles involving 4,121 participants (2,430 cases and 1,691 controls) were included. The overall pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) were 0.764 (95% CI: 0.746-0.781), 0.795 (95% CI: 0.775-0.814), 5.105 (95% CI: 3.313-7.865), 0.251 (95% CI: 0.174-0.364), 24.61 (95% CI: 12.22-49.54), and 0.93, respectively. In subgroup analyses, better diagnostic values were found for urine samples and East Asian Countries (China, Korea, and Taiwan). Conclusion: Urinary ApoA-I levels may serve as a favorable diagnostic marker for cancer.