Many studies have demonstrated that the expression levels of glycolysis related genes such as 6-phosphofructto-1-kinase (PFK-1), PKM2 and 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase genes (PFKFB1-4), are increased in tumor cells under hypoxia condition126,127. Here, PKM is linked to neoplasm.