STAT3 and cancer: There is currently strong evidence to suggest that aberrant activation of signal transducer and activator of transcription 3 (STAT3) represents a key step in the neoplastic process in human cancers through the induction of anti-apoptosis, cell proliferation, angiogenesis, invasion, and metastasis (Siveen et al., 2014; Chai et al., 2016; Shanmugam et al., 2016; Wong et al., 2017).