CXCL1 and cancer: In view of our published findings indicating that higher expression levels of PD-L1 in TNBC cells lead to increased extracellular levels of the pro-metastatic chemokines CXCL8, CXCL1 and CCL5 [66], our current observations propose that by inhibiting sTNFR1 and sTNFR2 expression, PD-L1 contributes to increased production of the pro-metastatic chemokines, and thus to the pro-malignancy potential of the cancer cells.