"HT29 tumors express a variety of growth factors, including VEGF, TNF??, TGF??, TGF??, PDGF and IL-8; it is not known whether HT29 cells also express bFGF. VEGF is most commonly associated with the hypoxic core of the tumor, and is transcriptionally regulated by hypoxia, whereas bFGF and other factors are associated with the growing edge of the tumor (Shweiki, et. al., supra, 1992; Kumar et al., On" . . . . .