Oliveira et al. [27] found a higher prevalence of EBV in low grade and luminal A breast cancer, while both Corbex et al. [61] and Pai et al. [138] reported a higher prevalence of EBV in triple negative breast cancer; similarly, Mashaly et al. [153] reported an association with more aggressive tumors and an increased frequency of EBV subtype D in breast cancer patients; the same subtype was also associated with negativity for progesterone receptor and negativity for HER2. This evidence concerns the gene PGR and breast cancer.