Although it has previously been shown that VEGF secreted from hypoxic glioma tumor cells can increase GLUT1 expression in ECs (Yeh et al., 2008), several other factors that are present in the tumor microenvironment such as cytokines, hypoxia and estrogen (Yizhak et al., 2014; Cantelmo et al., 2016; Trenti et al., 2017) can also increase EC PFKFB3 expression. This evidence concerns the gene VEGFA and neoplasm.