STAT3 and cancer: Napthoquinones have been studied for their anti-cancer properties against several cancers, including prostate cancer.56,57 They can inhibit growth and induce apoptosis in cancer cells.58 In a xenograft model of PC-3M-luciferase prostate cancer cells, treatment with Plumbagin, a quinoid isolated from the roots of Plumbago zeylanica, inhibited tumor growth and decreased metastasis57 associated with decreased levels of protein kinase C, survivin, Bcl, different MMPs, and STAT3 phosphorylation along with induction of inducible nitric oxide synthase.