A new system for studying tumor growth and metastasis using the popular green fluorescent protein (GFP) tag is being adapted as a possible platform for testing anti-angiogenic compounds. The basic approach, described recently in the Proc. Natl. Acad. Sci. USA (97, 1206–1211, 2000), employs rodent and human tumor cell lines that express high levels of GFP. When injected into appropriate mouse strains, the cells can be traced in real time using a noninvasive whole-body imaging technique. In the initial tests of this concept, researchers were able to observe the growth of primary tumors and metastases in vivo. According to Andrew Perry, president of AntiCancer A/C's (San Diego, CA) diagnostic division, at the March meeting of the American Association of Cancer Research in New Orleans, LA, scientists from the company will describe additional experiments that they say demonstrate the model's utility for studying angiogenesis in tumors. Perry said in a statement that “until now research has been significantly impeded through lack of a convenient and relevant animal model of angiogenesis. We anticipate our new product will greatly enhance the research.”