CAD and hepatocellular carcinoma: A downregulation of CPS1 has frequently been associated with HCC in literature.7,8,22 The upregulation of CAD in HCC, which has been previously reported, was hypothesized to be linked to the downregulation in CPS1 through an increased availability of glutamine due to the halting of urea cycle.23–25 This study aimed to develop a network which explored the relationships between genes and metabolites in disease, and to test the applicability of such networks, using CPS1 and CAD in HCC as an example, and using information from KEGG, HMDB and HPA to develop the network.