The transcriptional coactivator PGC-1α (peroxisome proliferator-activated receptor-γ coactivator-1α) is induced by hypoxia and interacts with the orphan nuclear receptor estrogen-related receptor-α (ERR-α) to stimulate VEGF, angiopoietin 2 and other angiogenic factors expression and promote angiogenesis in cultured muscle cells and skeletal muscle in vivo, as well as in cancer cells (11). Here, ESRRA is linked to cancer.