STAT3 and neoplasm: ROS can regulate a lot of signaling pathways through transcription factors, such as nuclear factor-kappa-B (NF-κB), signal transducer and activator of transcription 3 (STAT3), HIF-1α, kinases, growth factors, cytokines and other proteins and enzymes, which are related to cell transformation, inflammation, tumor survival, proliferation, invasion, angiogenesis and tumor metastasis [60].