We show that tumor-derived lactate activates mechanistic target of rapamycin complex 1 (mTORC1)-carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase (CAD) signaling, enhancing de novo pyrimidine biosynthesis and pre-ribosomal RNA synthesis, thereby promoting ECM protein translation. The gene discussed is CAD; the disease is neoplasm.