VEGFA and neoplasm: For systemic delivery, 1.5 nmol of VEGF-siRNA-PEG/PEI PEC was given intravenously into the tail vein of mice at 0, 4, 10, 18 and 28 days, exerting drastic tumor inhibitory effects (86%) (tumor volume, 196 mm3) relative to the control group (tumor volume, 1400 mm3) [103].