Metabolites present in the 31P-NMR spectrum from cancer cells include17, 18, 19 the product of choline kinase (CK) and phospholipase C (PLC), phosphocholine (PCho) and the product of Phospholipase A2 (PLA2) glycerophosphocholine (GPC) from the breakdown of phosphatidylcholine. Here, CHKA is linked to cancer.