The qPCR analysis of PHGDH and D2HGDH expression in tissue samples, along with TCGA database analysis, revealed that PHGDH expression was highest and D2HGDH expression was lowest in TNBC tumors compared to other breast cancer subtypes (Fig. 1G-H, Figure S1E-F). Here, D2HGDH is linked to breast cancer.