STAT3 and neoplasm: Recent studies have demonstrated that HCMV-US28 induces cyclo-oxygenase-2 (COX2) expression, production of vascular endothelial growth factor (VEGF) and tumor formation in vivo, via activation of nuclear factor kappa B (NF-kB), STAT3 phosphorylation and accumulation of beta cathenin in the cell nucleus.