Production of Tumors in Syrian Hamsters After Oral Administration of Polyoma Virus

Summary

Polyoma virus was administered orally to young Syrian hamsters twice weekly for 68 weeks. Four of the 20 animals developed subcutaneous sarcomas 14, 18, 18 and 44 weeks after initiation of the experiment. The tumors were similar to those produced in hamsters by subcutaneous inoculation of the virus. The 4 animals with subcutaneous tumors and 7 animals from the infected groups without subcutaneous tumors have been necropsied, and no evidence of primary tumors of the gastrointestinal tract has been found. No tumors have been observed in the remaining animals in the group fed virus and in 10 control animals given tissue culture fluid free of virus. These findings indicate that although oral administration of an oncogenic virus may not result in primary tumors of the gastrointestinal tract, subcutaneous tumors may be produced.