TMPRSS2 and prostate cancer: Functional and mechanistic studies indicate that ERRα can promote the hypoxic growth adaptation of prostate cancer cells via its stabilization and augmentation of HIF-1 signaling [66], and also can form a reciprocal regulatory loop with an oncogenic transcription factor ERG on the regulation of TMPRSS2:ERG fusion gene and thus to promote the malignant growth of prostate cancer [39].