): The Jackson Laboratory (TJL) requests funding (1) for continuation of its well-established postdoctoral research training program in the genetics of cancer and (2) initiation of a redefined Ph.D. program in mammalian cancer genetics consisting of course work undertaken primarily at the University of Maine (UMaine) and thesis research at TJL (degree to be conferred by the UMaine). Thirteen members of the TJL Research Staff form an interdisciplinary pool of trainee preceptors who are investigating the genetic basis and impact of immunologic, endocrine, and age-related factors on the development and progression of endogenous tumors in the mouse. Experimental work in these genetically-defined animal models provides the opportunity to test hypotheses regarding the origins of cancer and to model new diagnostic and therapeutic modalities. Emphasis is placed on the use of the Laboratory's special inbred, spontaneous and induced- mutant mice in the individual research projects involving mouse models of cancer. TJL Postdoctoral program (3 trainees). Each trainee is sponsored by a TJL faculty member in a program tailored to the trainee's individual needs. Trainees devote their major effort to bench research, and are integrated into TJL seminars, courses, workshops, and research interest groups. The primary training facility is TJL, a private, independent research center. TJL is an NIH Basic Cancer Research Center, raises 3 million mice annually, and has held NIH research training grants continuously since 1956. Following a disastrous fire in 1989 TJL developed a Strategic Plan which called for an increase in the number of Research Staff scientists (independent investigators) from 24 in 1991 to a total of 40 by 1996, the rebuilding of the animal facility, and the construction of a new research wing. In the three years since the Plan was adopted thirteen new Staff members were added, a new animal facility and a new 49,000 square foot research building were completed, a series of modern scientific services were established, a graduate course was initiated, and the pre- and postdoctoral training programs have been expanded. TJL-UMaine Cooperative Ph.D. program (2 trainees). In collaboration with the TJL faculty, faculty members from UMaine co-advise graduate students in cancer genetics. During the first 2 years trainees will do rotations at TJL and course work at UMaine; the degree will be awarded by UMaine. A primary source for the cooperative program will be students in TJL's renowned Summer Student Program, which has a high enrollment of minorities, and students recruited by standard means from undergraduate academic institutions. The training opportunities at TJL in cancer genetics, using the mouse as an experimental animal model, are unique because of the concentration of mammalian geneticists with diversified interests in the cancer problem. Scientists at TJL foresee a need for a cadre of research scientists trained to view the complexity of the genetic changes leading to carcinogenesis and progression in intact animal model systems. This philosophy, an integral part of the Laboratory's Strategic Plan, has dictated expansion of the TJL training program.