Constitutive STAT3 phosphorylation in tumor cells is usually driven by the overproduction of key cytokines and growth factors, such as IL-6, IL-10, EGF, HGF, Her2/Neu, and VEGF, or their receptors, as well as aberrantly activated cytoplasmic kinases, such as Src, among others (57). The gene discussed is ERBB2; the disease is neoplasm.