STAT3 and cancer: Inflammatory cells produce tumor necrosis factor (TNF)-α (King, 2015), transforming growth factor (TGF)-β (Feng et al., 2017), interleukin (IL)-6 (Wouters et al., 2014), and other pro-inflammatory factors, which activate NF‐κB/STAT3 pathways and induce epithelial-to-mesenchymal transition (EMT) as well as cancer metastasis (Narayan and Kumar, 2012; Gray et al., 2014).