GCG and cancer: KEGG pathway analysis indicated that most of the KEGG metabolic pathways, including the TCA cycle, glucagon signaling pathway, alanine, aspartate and glutamate metabolism, GABA-ergic synapse, glyoxylate and dicarboxylate metabolism, central carbon metabolism in cancer, choline metabolism in cancer, et al, were related to lipids and lipid-like molecular metabolites.