GLUL and neoplasm: For example, aberrant Wnt signaling upregulates glutamine synthetase (GLUL) to increase glutamine levels and activate the mammalian target of rapamycin (mTOR) signaling pathway to facilitate tumor progression [12], and loss of p53 activates sterol regulatory element binding transcription factor 2 (SREBP-2)-driven mevalonate pathway to promote liver tumorigenesis [13].