ATX-LPA signaling in tumor microenvironment. ATX hydrolyzes LPC to produce LPA from circulating LPC and platelet-derived LPC. ATX is mainly released into the tumor microenvironment by tumor-adjacent adipocytes and B lymphocytes but cancer cells and cancer stem cells also secrete this enzyme. LPA signals through its receptors to induce proliferation and invasion in cancer cells and cancer stem cells. LPA signaling induces angiogenesis through the recruitment of CAFS; it also reduces cytotoxic immune response via CD8 T cells. ECM (extracellular matrix).