VEGF and CNS leukemia. (A) Hypoxic conditions within the CSF induce the secretion of VEGF by leukemic cells. VEGF may further enhance the transendothelial migration of leukemic cells from the blood into the subarachnoid space and/or enhance the survival of leukemic cells in the CNS. (B) Treatment with bevacizumab, an antibody against VEGF that has been approved by the US Food and Drug Administration for the treatment of cancer, reduces the load of CNS leukemia. (C) Hypothetical role for VEGF in testicular involvement by ALL. Professional illustration by Somersault18:24, with assistance from Lev Yakimov.