TNF and breast carcinoma: Furthermore, the innate immunity, particularly the dendritic cells and M1 macrophages in the tumor microenvironment, have also been shown to contribute to the abscopal effect in breast cancer and in situ studies [16,17]. Conversion of anti-inflammatory M2 to pro-inflammatory M1 macrophages upon irradiation leads to upregulation of tumor necrosis factor (TNF)-α, enhancing the anti-tumor activity of the innate immune system as well.