Epstein-Barr Virus Infection and Risk of Breast Cancer: An Adaptive Meta-Analysis for Case-Control Studies

Context: The association between 'Epstein-Barr' virus (EBV) and breast cancer risk still remains controversial. A Systemic Review (SR) published in 2012 reported that there might be a statistically significant association between EBV and risk of breast cancer. However, errors were found in the appraisal process of the concerned SR. Objectives: The aim of this report was to conduct an adaptive meta-analysis with additional extraction of relevant papers published up until September 2015. Data Sources: The lists of references, cited articles and related articles provided by PubMed were made using the articles selected in the previous SR. Study Selection: Among these articles, only case-control studies using Polymerase Chain Reaction (PCR) techniques to detect EBV DNA in tissues were selected. Data Extraction: The summary odds ratio (SOR) and the 95% confidence interval (CI) were calculated though meta-analysis. Results: A total of 20 case-control studies were selected, and the total numbers of subjects in the case and control groups were 1947 and 1010, respectively. The findings of this meta-analysis revealed that EBV infection might increase the risk of breast cancer (SOR = 3.84, 95% CI: 2.24-6.58; I-squared = 62.2%). Sub-group analyses by region, sample type, and control tissue showed that a statistical significance of the risk was still secured. Conclusions: The findings of the meta-epidemiological study support that EBV infection may increase the risk of breast cancer. Nested case-control studies are required in the future.