Transplantability, Morphology, and Behavior of Polyoma Virus-Induced Hepatic Hemangiomas of Hamsters

The angiomatous lesions developing in the liver of hamsters within 30 days after inoculation with polyoma virus have a low incidence of transplantability. Those that do transplant develop as cystic hemangiomas composed of cells suggesting origin from phagocytic reticuloendothelium. During transplantation some of the tumors acquire further irreversible structural and behavioral characteristics of malignant tumors. The latent period, growth rate, structure, and incidence of metastases have been studied in cystic hemangioma 265 for more than 90 transplant generations. One line of this tumor acquired the ability to metastasize rapidly and consistently and to grow without inhibition in polyoma virus-infected hosts. Efforts to alter the inherent characteristics of the tumor have failed. Like other transplantable tumors, progression seems to occur in polyoma virus-induced tumors independent of the inciting cause.