Fig 1. Meta-analysis of EBV positivity in breast cancer tissue samples.
Random effects meta-analysis was performed on the proportions of samples that were positive for EBV rather than relative risks, because only six studies (including ours) included paired normal samples. Proportions had 95% confidence intervals derived from the Normal approximation to the binomial with 0.5 added to zero counts. Estimates of the average proportion positive were calculated for all studies and for each assay type that was used in multiple studies. Results of studies that analyzed breast tissue samples for EBV are shown according to the method of analysis. The overall strength of association for each type of analysis, and the overall strength of association for all studies are shown at the bottom of the figure. There was considerable heterogeneity in the EBV analyses (I2 = 98.6%).