Starting without a priori knowledge, we detected metabolic flux changes, which led to an increased glutamine contribution to acetyl-CoA, show that A549 lung cancer cells produce N-acetylaspartate, a compound which is well known to have an important function in neuronal tissue, but was until very recently [23] not known to be produced in other tissues, and show that silencing its biosynthetic enzyme NAT8L exerts a negative growth effect. The gene discussed is ASPNAT; the disease is lung carcinoma.