Figure 5.

Interleukin‐6 (IL‐6) and transforming growth factor beta (TGF‐β) phosphorylate STAT3 in naïve T cells. Naïve T cells are induced to differentiate into regulatory T cells by TGF‐β in the absence of IL‐6. ROR‐γt is activated to induce differentiation of the naïve T cells into Th17 cells, which produce IL‐17 and TNF‐α. Nuclear factor‐κB (NF‐κB) activated by IL‐17 or TNF‐α stimulation induces expression of IL‐6, which phosphorylates STAT3 in cancer cells. These steps result in programmed cell death 1 ligand 1 (PD‐L1) expression in ovarian cancer (OC) cells and reactivation of IL‐6 and STAT3 through a positive feedback loop