MMP9 and cancer: The role of the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) pathway is a well‐known mediator of tumorigenesis in different tumors, and is associated with migration and invasion of cancers by increasing expression of MMP2 and MMP9.22, 23, 24 Phosphorylation of STAT3 on Tyr705 is the major mechanism of STAT3 activation, which is mediated by JAK upon stimulation of the heterodimeric gp130/cytokine‐specific receptor complex by the IL‐6 family of cytokines, including IL‐6.25