PHGDH and neoplasm: Remarkably, either KO or inducible-KD of PHGDH markedly inhibited the self-renewal ability of GSCs, as evidenced by the result of the tumor sphere formation experiments (Fig. 2B, C and Supplementary Figure S3B), the diminished GSC viability (Fig. 2D and Supplementary Figure S3C), and by the results of the in vitro limiting dilution assay (Fig. 2E, F).