CA9 and neoplasm: HIF-1α is then able to translocate to the nucleus, where it dimerises with its constitutively expressed partner HIF-1β (also known as aryl nuclear hydrocarbon translocator) and then binds to the hypoxic response element of genes that enhance tumour cell survival such as glycolysis (Glut1), angiogenesis (for example, vascular endothelial growth factor (VEGF)), iron metabolism (transferrin), pH control (carbonic anhydrase (CAIX)) and haemoglobin synthesis (erythropoietin) (reviewed in [1]).