Their induction may be driven by a number of factors released by tumors and tumor-associated cells, including VEGF (39), TGFβ (40), IL-1β (41), IL-13 (42), GM-CSF (43), prostaglandins (44), reactive oxygen species (ROS) (45), and components of the complement system (46). This evidence concerns the gene TGFB1 and neoplasm.