We comparatively examined nude mice and hamsters as to their suitability as recipients of human cancers. CD-1 nude mice and golden hamsters immunosuppressed with anti-hamster thymocyte serum were used. Nude mice were superior in the areas of primary transplantation and subsequent transfer and maintenance. However, growth of tumors transplantable to both animals (a lung cancer line LC-1, a colon cancer line RPMI4788) tends to be better in hamsters than in nude mice. The better development of LC-1 and RPMI4 788 cells in hamsters than in nude mice appears to be related to the superior gain in body weight shown by hamsters
