Whereas HIF-1α is mostly responsible for activation of glycolytic pathway genes (e.g. HK1 (hexokinase 1) and HK2 (hexokinase 2)), HIF-2α is involved in regulation of genes responsible for cell cycle progression (e.g. cyclin D1), tumor growth, erythropoiesis (EPO (erythropoietin)), and maintaining stem cell pluripotency among other functions (14, 15). Here, HK1 is linked to neoplasm.