CPS1 and hepatocellular carcinoma: Most importantly, literature review provided sufficient evidence that CPS1 is commonly downregulated in HCC, with TCGA reporting CPS1 abnormalities in 5.92% of liver cancer cases.6 A study theorized that the downregulation of CPS1 in HCC may be due to the loss of differentiation in hepatocytes, but this was excluded, since other liver-specific genes were found to be adequately expressed.9