PHGDH and cancer: The AAV-mediated ectopic expression of PHGDH-T57A and PHGDH-R135W in the liver of wild-type mice that retains normal serine synthesis did not change the levels of 3-PGA or other glycolytic intermediates (Fig. 5c; Supplementary information, Fig. S5d), emphasizing a causative role of availability of 3-PGA itself in cancer growth.