STAT3 and neoplasm: Precise regulation of STAT activation is critical for eliciting the appropriate responses to extracellular signals [193], but persistent activation of STAT3 via phosphorylation by cytokines is mediated through JAK [194] and is required for the survival of tumor cells by promoting the upregulation of genes that encode anti-apoptotic proteins, angiogenic factors, and cell cycle regulators [193].