Extracellular LPA is predominantly produced by autotaxin (ATX, also referred to as ENPP2 [ectonucleotide pyrophosphatase/phosphodiesterase family member 2]), an ectoenzyme that was originally identified as a tumor-cell motility-enhancing factor (Stracke et al., 1992). The gene discussed is ENPP2; the disease is neoplasm.