HIF1α and HIF2α dimerize with the Aryl Hydrocarbon Receptor Nuclear Translocator (ARNT) to form HIF1α/ARNT (HIF1) or HIF2α/ARNT (HIF2) complexes that induce expression of the genes that regulate metabolism, angiogenesis, cell proliferation and the epithelial-to-mesenchymal transition.13, 14, 15 Thus, HIF-mediated transcription response is critically important for ccRCC disease. The gene discussed is HIF1A; the disease is nonpapillary renal cell carcinoma.