TNF and breast cancer: Our study aims were concentrated into three axes: i) EBV DNA detection in both BC tissue and peripheral blood mononuclear cells (PBMCs); ii) the IFN-γ and TNF-α intracellular immunostaining test combined with flow cytometry analysis, chosen owing to the fact that cytokines, primarily secreted by activated T cells and natural liller cells, play a crucial role in the response to persistent viral infections [26]; iii) patient clinical outcome and pathological characteristics.