ATX was originally characterized as a secreted enzyme with an autocrine motility factor from the conditioned medium of A2058 human melanoma cells20, and this enzyme is identical to lysophospholipase D (LysoPLD), which converts lysophosphatidylcholine (LPC) to a bioactive lipid mediator, lysophosphatidic acid (LPA), and choline21,22. The gene discussed is ENPP2; the disease is melanoma.