Further analysis has revealed that the signal reported in Extended Data Fig. 1c of this Letter is attributed to phosphorylethanolamine, not carbamoyl phosphate. A newly developed derivatization method revealed that the level of carbamoyl phosphate in these NSCLC extracts is below the detection threshold of approximately 10 nanomoles. These findings do not alter the overall conclusions of the Letter; see associated Amendment for full details. The Letter has not been corrected online.