FASLG and neoplasm: For example, low expression of MHC I and MHC II on the surface of tumor cells or expression of immunosuppressive molecules such as vascular endothelial growth factor (VEGF), interleukin-10 (IL-10), Fas ligand (Fas-L), TGF-β and prostaglandin E2 (PGE2) to mediate immune escape.