Also known as phosphogluconate pathway or the hexose monophosphate shunt, the pentose phosphate pathway (PPP) branches from glycolysis at the first committed step of glucose metabolism. With glucose-6-phosphate as a primary substrate, this pathway is catalyzed by hexokinase and generates building blocks for ribonucleotides synthesis and NADPH, which is required for the clearance of reactive oxygen species and fatty acids synthesis. It is shown in some report that pentose phosphate pathway plays a key role in assisting glycolytic cancer cells to combat against oxidative stress and meet their anabolic demands.