[Human viral carcinogenesis. RNA-tumor-virus like structures in human leukemia, lymphomas and sarcomas]

As a contribution to the solution of the etiological question of human neoplasias, human leukemias, lymphomas and sarcomas were shown to contain viral structures and/or virus-like particles that resembled analogous animal RNA tumor viruses or their structures. The human particles possess 1. a single stranded, high molecular weight 70s RNA, 2. a RNA-dependent DNA-polymerase, 3. a characteristic density of 1.16--1.19 g/cm3, and 4. a base sequence of their RNA related to the RNA of analogous animal RNA tumor viruses. Although a biological activity of these particles has not been shown, their similarity with analogous animal viruses, their presence in certain neoplasias, and their absence in normal, non-embryonal tissues make some function of these particles in human carcinogenesis likely.