The purpose of the Animal Core is to provide investigators on this Molecular Targets Program access to mouse models of human tumors and to the technical expertise needed to perform these animal experiments. In the initial years of this grant, the mouse studies will involve pharmacokinetic/pharmacodynamic (PKJPD) evaluations of the drugs and their associated molecular targets as discussed in the specific projects. In future years, as new agents are presented, the Animal Core will evaluate these for antitumor activity and perform PK/PD studies in mouse models. We will primarily use severe combined immune deficient (scid) mouse models, but other mouse systems can also be used. Dr. Charles Taylor and other investigators established a scid mouse colony at the University of Arizona in 1988. Maintaining the colony locally results in tremendous cost savings compared to purchasing scid mice from commercial vendors. The Animal Core (Core C) will provide 3 primary services to the investigators on this grant: 1. Assist with the design of experiments using scid mouse models of human tumor growth and metastasis. 2. Provide technical expertise and consistency in performing scid mouse experiments. 3. Maintain the scid mouse colony and ensure adequate availability of mice for required experiments.