The hypoxic microenvironment upregulates not only the expression of HIF-1 and VEGF (via the PI3K/Akt/mTOR pathway), but also induce the transcription factors nuclear factor-kappa B (NF-κB) and signal transducers and activators of transcription 3 (Stat3), which are constitutively active in most cancers, including PCa. Here, STAT3 is linked to cancer.