STAT3 and cancer: Stimulation of the malignant properties of epithelial and cancer cells by IL-1 and IL-6 is directly related to the ability of these cytokines to activate proto-oncogenic transcription factors, such as signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which exert angiogenic, immunosuppressive, and antiapoptotic effects in the tumor microenvironment.