STAT3 and gastric cancer: Moreover, IL-6 mediated the interaction between gastric cancer cells and CAFs, and contributed to chemoresistance of gastric cancer cells; CAF-derived IL-6 induced activation of the signal transducer and activator of transcription 3 (STAT3) pathway reduced chemotherapy-induced apoptosis, thus promoting the chemoresistance of gastric cancer cells; in patients with gastric cancer, a poor response to chemotherapy is associated with the expression level of IL-6 [15].