In esophageal squamous cell carcinoma (ESCC), AGK directly binds to the Janus kinase homology 2 (JH2) domain of JAK2 to block the inhibition of JAK2 mediated by JH2, which leads to the activation of the JAK2/STAT3 signaling pathway and enhances the tumorigenicity of ESCC cells in vivo and in vitro (Chen et al., 2013). The gene discussed is STAT3; the disease is esophageal squamous cell carcinoma.