JAK2 and esophageal squamous cell carcinoma: Here, using cytokine microarray, we verified that circNF1 caused ESCC cells to secrete more IL-6, a recognized cytokine for activating the JAK2/STAT3 axis, inferring that IL-6 acted as a key intermediate factor in circNF1-interacted JAK–STAT3 signaling pathway [23].