ENPP2 and cancer: Expression of ATX is elevated in multiple cancer types [4–12] and experimental forced expression of ATX or LPA receptors (LPA1, LPA2, LPA3) in the mammary gland of MMTV-driven gene transgenic mice induces the development of spontaneous breast tumors and metastasis formation, reinforcing the importance of the ATX/LPA track in oncogenesis and metastasis [13].