Virus-like particles in long-term transplanted hamster tumors.

Among the studied long-term transplanted skin tumors in hamsters virus-like particles (VLP) have been disclosed by electron microscopy in two squamous cell carcinomas and one fibrosarcoma but not in three melanoma lines. The great majority of the particles have exhibited structure and intracisternal position typical for the R or H type VLP. Their amount have greatly varied in the different lines and within the period of study. In the fibrosarcoma cells A type particles have also been observed. The available literature on R type VLP have been reviewed and their possible role in oncogenesis was discussed.