PHGDH and adenocarcinoma: Moreover, higher mTORC1 activity, stronger nuclear ATF4 staining and increased expression of PHGDH was also detected in NEPC tumors compared to adenocarcinoma, suggesting the critical role of mTORC1/ATF4/PHGDH metabolic axis in increased cell proliferation and epigenetic reprogramming during NEPC development (Reina-Campos et al., 2019).