Adenovirus-like transformation of hamster embryo cells mediated by Simian virus 40

Primary hamster cells, derived from embryos of 10 days gestation, were exposed in culture to the oncogenic effect of the DNA virus SV40. While the fibroblastoid cells transformed soon after virus inoculation, the small, round or oval cells also present preserved their characteristic mophologic features for a long time. When these cells finally transformed under the influence of SV40, they developed the capacity to induce, in the homologous host, small-, round-cell sarcomas, that were morphologically indistinguishable from neoplasms usually produced by adenoviruses. These findings indicate that different cells differ in their susceptibility to virus-mediated neoplastic transformation. They demonstrate also that the morphology of virally induced tumors is not always pathognomonic of their specific etiology.