Tissue Culture Characteristics and Oncogenicity of Three SV40-Induced Hamster Tumors.

Three spindle cell sarcomas induced in hamsters by neonatal inoculation of SV40 were explanted and maintained as cultured cell lines in vitro. The tumors varied widely from each other in morphology, plating efficiency, and growth rate in tissue culture. These appeared to be stable characteristics of the tumors. On transplantation into hamsters, the 3 tumor lines demonstrated no difference in tumorigenicity or rapidity of tumor growth, indicating a lack of correlation between in vitro growth characteristics and malignant potential. During the period of observation, no increase or decrease in oncogenicity with continued passage in vitro or in vivo occurred, although some dedifferen-tiation of the tumor cells took place during passage in tissue culture. All tumors and in vitro lines were found to contain the SV40 tumor antigen and to be free of infectious SV40.