Angiogenesis in the hollow fiber tumor model influences drug delivery to tumor cells: Implications for anticancer drug screening programs

The National Cancer Institute uses the hollow fiber assay as part of its sc reening program for anticancer drug discovery. Angiogenesis to hollow fiber s implanted s.c. has not been reported, thereby raising concerns about the efficiency of drug delivery and its subsequent effects on chemosensitivity, By extending postimplantation times beyond the 6-day period presently used , extensive vascular networks develop, resulting in both increased delivery and chemosensitivity to doxorubicin. This study suggests that present prot ocols used to evaluate compounds may produce false negative results, and ad ditional studies to determine the predictive value of the assay are require d.