VEGF/VPF production by PEL, Burkitt's lymphoma, and solid tumor cells. PEL cells, Burkitt's lymphoma cells, and solid tumor-derived cell lines were cultured (1 × 10⁶cells/well) for 72 hours in 6-well plates (2.5 mL/well). A-375, melanoma; MDA-MB-486, breast cancer; SK-N-MC, neuroblastoma; SW-480, colon carcinoma; DU145, prostate carcinoma. VEGF/VPF levels in the culture supernatants were determined by ELISA. Results represent the mean (±SD) of 3 independent experiments.