 Although taxanes bind to the microtubular network in cells that is essential for mitotic and interphase cellular functions, the mechanism by which these agents induce cell death is not entirely clear. Docetaxel has also shown dose-dependent anti-angiogenic activity. Thus, the mechanisms of anti-tumor activity of docetaxel remain unclear and combinations of signal transduction pathway inhibition andor anti-angiogenesis may provide potentiation of concurrent ZD 1839 and docetaxel therapy. 