NSC-74859 is an inhibitor of pSTAT3 that exhibits anticancer chemotherapeutic, antiviral, anti-fibrotic, and nephroprotective activities. NSC-74859 enhances the toxicity of doxorubicin by inhibiting the epithelial-to-mesenchymal transition (EMT) in vitro; it also enhances the efficacy of cetuximab in hepatic carcinoma cells. In cellular and animal models of hepatocellular cancer, NSC-74859 suppresses cell proliferation and inhibits tumor growth of xenografts. Inhibition of pSTAT3 results in decreased expression of genes encoding cyclin D1, Bcl-xl, and survivin. Additionally, NSC-74859 inhibits replication of varicella-zoster virus (VZV), a herpesvirus. In animal models of kidney injury, NSC-74859 decreases infiltration of inflammatory cells, decreases expression of fibronectin, smooth muscle actin, and collagen type-1 proteins, and inhibits proliferation; together, this increases apoptosis in renal interstitial fibroblasts.