Prognostic and Clinicopathological Significance of BAP1 Protein Expression in Different Types of Cancer-A Meta-Analysis.

Background and Aims: The prognostic value of BRCA1-associated protein 1 (BAP1) expression in different cancer types remains controversial. The aim of this study was to identify the prognostic and clinicopathological significance of BAP1 gene expression. Materials and Methods: The PubMed, Web of Science, and Embase databases were searched comprehensively for relevant studies. The pooled effects were calculated to investigate the association of BAP1 expression with cancer prognosis and clinicopathological features. The (2) and I-2 tests were performed to evaluate heterogeneity among the enrolled articles. If the p>0.05 and I-2 < 50%, a fixed-effects model was applied; and if the p<0.05 and I-2>50%, we used a random-effects model. Results: A total of 26 studies covering 8043 patients were included in the meta-analysis. The correlation between BAP1 expression and patient survival was evaluated for 10 different cancer types. The pooled hazard ratio (HR) of BAP1 expression and overall survival (OS) was 0.83 (95% confidence interval [CI]: 0.61-1.12) with heterogeneity (I-2=85.8%, p<0.001), which indicated that the expression of BAP1 had no obvious impact on patient survival in the all-cancer cohort. However, subgroup analyses indicated that cancer type, rather than other parameters (geographic region, detection method, sample size, or comparison method), lead to this heterogeneity. BAP1 expression was a favorable predicative factor for OS in clear cell renal cell carcinoma (HR=0.57, 95% CI: 0.47-0.69), non-small cell lung cancer (HR=0.55, 95% CI: 0.32-0.96), and uveal melanoma (HR=0.41, 95% CI: 0.27-0.62), while high expression of BAP1 was associated with poorer outcome in malignant pleural mesothelioma (HR=2.03, 95% CI: 1.67-2.47). Conclusion: Our study revealed that BAP1 expression tends to have different prognostic values in different cancer types. Clinically, BAP1 may serve as a promising marker for prognostic prediction for certain cancer types.