The top 10 pathways (Figures 3G, H; Table S4) showed that the changed metabolites were involved in lysine degradation (p < 0.01), GABAergic synapse (p < 0.05), oxidative phosphorylation (p < 0.05), citrate cycle (p < 0.05), cAMP signaling pathway (p < 0.05), glucagon signaling pathway (p < 0.05), alanine, aspartate, and glutamate metabolism (p < 0.05), central carbon metabolism in cancer (p < 0.05), pyruvate metabolism (p < 0.05), and sulfur metabolism (p < 0.05). The gene discussed is GCG; the disease is cancer.