title: Association of β2-microglobulin with the prognosis of non-Hodgkin's lymphoma: a meta analysis.
abstract: OBJECTIVE
  The influence of β2-microglobulin (β2-MG) on the prognosis of non-Hodgkin's lymphoma (NHL) remains controversial. This study performed meta-analyses to evaluate the prognostic value of β2-MG on the overall survival (OS) of NHL.
  
  
  METHODS
  Through a search of relevant literature in PubMed, EMbase, Science Direct, OVID and Wanfang databases from 1980-2013, the hazard ratios (HRs) of OS between the normal β2-MG group and the increased β2-MG group were retrieved, and the results were combined using a fixed effect model and a random effect model. Subgroup analyses were performed based on univariate and multivariate analysis results, and sensitivity analyses were performed to estimate the changes of the combined HRs. In addition, funnel plots and fail-safe numbers were used to estimate publication bias.
  
  
  RESULTS
  A total of 17 qualified publications were included, with a cumulative total of 2,479 cases. The result of heterogeneity examination showed that there was heterogeneity among all studies (P < 0.001, I(2) = 87%). In the random effect model, the combined HR was 2.71 (95% confidence interval [CI]: 1.91-3.85). The result of the total effect examination was statistically significant (Z = 5.59, P < 0.001).
  
  
  CONCLUSIONS
  The increased β2-MG level was an independent risk factor for the prognosis of NHL.
authors.affiliation: Department of Paediatrics, Yuhuangding Hospital Affiliated to Qingdao University Yantai 264000, China.
authors.forename: Xiao-Liang
authors.initials: XL
authors.lastname: Wang
authors.affiliation: Department of Paediatrics, Yuhuangding Hospital Affiliated to Qingdao University Yantai 264000, China.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Wang
authors.affiliation: Department of Paediatrics, Maternal and Child Health Hospital Jiangshan 324100, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: He
authors.affiliation: Department of Gastroenterology, Regenerative Medicine Research Center, Shandong International Biotechnology Park Yantai 264000, China.
authors.forename: Hong-Li
authors.initials: HL
authors.lastname: Zhai
keywords: meta-analysis; non-Hodgkin’s lymphoma; β2-microglobulin