Since the ecto-activity of LPP1 and LPP3 can contribute to the degradation of S1P [7] whose increased production and secretion is associated with the development of chemoresistance and stimulation of angiogenesis to support tumor growth, LPP1 and LPP3 could play important roles in these processes by controlling the levels of extracellular S1P. This evidence concerns the gene PLPP3 and neoplasm.