DAG1 and cancer: On the other hand, the CPS1‐induced upregulation of Asp could prevent invasion and metastasis of HCC cells by inhibiting the activity of phosphatidylcholine specific phospholipase C (PC‐PLC) to block the biosynthesis of diacylglycerol (DAG), leading to the downregulation of DAG‐PKC (protein kinase C) axis, which have been shown to promote invasion and metastasis of various cancer cells.