Prognostic Role of Beta-2 Microglobulin in Diffuse Large B-Cell Lymphoma: Systematic Review and Meta-Analysis of Observational Studies.

BACKGROUND: Evidence indicates that beta-2 microglobulin (β2M) plays a prognostic role in patients with diffuse large B-cell lymphoma (DLBCL). AIM: However, due to controversies among previous studies, this meta-analysis was conducted to evaluate the prognostic role of β2M in DLBCL patients. METHODS AND RESULTS: Relevant studies were identified through a systematic search using specific keywords in PubMed/Medline, Scopus, and Web of Science databases. Studies that provided complete information on the hazard ratio with a 95% confidence interval for β2M with respect to overall survival (OS) and progression-free survival (PFS) in multivariate models were included in the meta-analysis. A total of 30 studies, encompassing 25 128 patients, were included in this meta-analysis. The pooled analysis demonstrated a significant association between elevated β2M levels and poor OS in DLBCL patients (HR Pooled: 1.65, 95% CI: 1.45-1.88, p-value < 0.01). Similarly, increased β2M levels were significantly associated with lower PFS in DLBCL patients (HR Pooled: 1.54, 95% CI: 1.39-1.70, p-value < 0.01). CONCLUSION: The available evidence suggests that β2M serves as an independent prognostic marker with significant effects on OS and PFS in DLBCL patients. Elevated serum β2M levels are associated with poor prognosis and worse OS and PFS outcomes in DLBCL patients.