Significantly, administration of the PHGDH inhibitor NCT‐503 in the established eIF3f high PDX tumors (CRC#116, 216) attenuated tumor growth; while NCT‐503 had little impact on the growth of eIF3f low PDX tumors (CRC#309, 490) (Figure S5D and S5E, Supporting Information). The gene discussed is PHGDH; the disease is neoplasm.