STAT3 and cancer: In RCC tumors, activation of transcription factors, such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), signal transducer and activator of transcription 3 (STAT3) and hypoxia-inducible factor 1α (HIF1α) increase the production of angiogenic factors and inflammatory mediators, such as interleukins IL-1β, IL-6, IL-23 and tumor necrosis factor α (TNFα) and chemokines, creating a cancer-associated inflammatory TME [33,34,35] (Figure 1).