The long term objective of this research program is to characterize human tumor stem cells from primary explants with respect to their biological properties. We intend to and have applied relatively simple and rapid techniques to assess stem cell sensitiviiy to cytotoxic drugs and radiation. Information derived from these studies would be utilized to identify promising new agents with activity against various types of human cancer, and to select potential agents for use in refractory tumors. The overall objective is to develop a rational and experimentally testable basis for predictive cancer chemotherapy.