Epstein-Barr Viral Infection and the Risk for Breast Cancer: A Systematic Review.

: The prevalence of breast cancer has increased and has currently become one of the most common cancers. Although the majority of the world's population is infected with Epstein Barr Virus (EBV) during their lives, the severity of symptoms varies and not everyone infected with EBV is diagnosed with cancer. EBV might increase the risk for breast cancer either by activating the HER2/HER3 signaling cascades or by creating a state of prolonged immune stimulation. : A systematic search of several electronic databases including PubMed, ScienceDirect, Cochrane, EBSCOhost, JSTOR, and Scopus, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted. The primary outcome of this review was to assess the prevalence of people with breast cancer that had a prior EBV infection. : For this review, 24 case-control studies were accepted. Our analyses included 1.989 breast cancer cases versus 1.034 control cases. EBV was found to be present in 27.9% of breast cancer cases versus 8.02% found in the normal breast tissue of controls. All affected people were women with a mean age was 48.19 years. The most common type of breast cancer found in EBV-infected tissues was invasive breast cancer. Cases were reported sporadically in a wide geographical distribution, and the prevalence varied from 4.6% - 64.1%. : A previous EBV infection might be associated with a higher risk for breast malignancy. The most common type is invasive cancer. It mainly affects women and geographical variances are observed. More studies are necessary to elucidate the role of EBV in the mechanisms of breast cancer. Also, it is crucial to improve the prevention and treatment strategies.