Induction of mVEGF in oHSV-injected tumors. A673 xenograft tumors were injected with rRp450 or PBS control and tumors were harvested at 3 days. The amount of (a) tumor-derived hVEGF (n = 7) and (b) stroma-derived mVEGF was determined by ELISA (n = 7). Error bars represent SEM. ELISA, enzyme-linked immunosorbent assay; hVEGF, human vascular endothelial growth factor; mVEGF, mouse vascular endothelial growth factor; oHSV, oncolytic herpes simplex virus; PBS, phosphate-buffered saline.