MTOR and nicotine dependence: In the CSE group, the pathways of nicotine addiction, mammalian target of rapamycin (mTOR) signaling pathway, antifolate resistance, glycerophospholipid metabolism, choline metabolism in cancer, central carbon metabolism in cancer, d-glutamine and d-glutamate metabolism, synaptic vesicle cycle, and arginine biosynthesis significantly enriched (Fig. 3d, e).