STAT3 and neoplasm: Also sometimes considered as a pan-assay interference nuisance compound (PAIN), 31 can interact with a variety of tumor-related targets and pathways, such as nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), STAT3, PTEN, Bcl-2, p53, and PPAR-γ, etc., to exert anti-proliferation, induction of apoptosis and oxidative stress, cell cycle arrest, anti-angiogenesis, and cellular metastasis [109,112,113,114].