Fig. 1B) emphasise the robustness of the phenomenon of a hypoxia dependent upregulation of SSP enzymes in cancer.34,41 Furthermore, we could show that overexpression of PHGDH protected GBM cells from hypoxia-induced cell death (Fig. 4e) and sustained NADPH/NADP+ ratios under starvation conditions (Fig. 4f). This evidence concerns the gene PHGDH and cancer.