CD274 and breast cancer: Administration of paclitaxel, etoposide or 5-flurouracil dose- and time-dependently increases PD-L1 surface expression in breast cancer cells, possibly through the JAK/STAT, MAP kinase and/or PI3K/AKT mechanisms, and acts concomitantly with IFNγ to augment the expression of PD-L1 (Table 2) [82].