IL6 and esophageal squamous cell carcinoma: For example, Zhao et al. (2021b) discovered that interleukin-6 (IL-6) secreted by cancer-associated fibroblasts (CAF) and miRNA-21 (miR-21) packaged in exosomes activate IL-6 signaling and transcription activating factor 3 (STAT3), leading to cisplatin resistance in patients with ESCC.