Simian Adenovirus Type 7 (SA-7) Induces Tumours of Nerve-supporting or Paraneural Cell Origin in Newborn Hamsters

Simian adenovirus type 7 (SA-7) was found to induce tumours originating from nerve-supporting or paraneural cells in newborn hamsters, regardless of injection site or tissues. SA-7 induces glioblastomas characterized by definite localization (subependymal regions) and its main cell type, bipolar spongioblast-like cells, in the brain of hamsters inoculated as newborns. When the eyes of newborn hamsters were directly inoculated, SA-7 failed to induce retinoblastoma (0/27), but retro or peri-bulbar SA-7 tumours frequently occurred in tissues closely related to the peripheral nerve apparatus, including the oculomotor nerve or ciliary ganglion. These tumour cells were situated like stromal cells in these nerve tissues. The histological features of the orbital tumours were similar to those of SA-7-induced subcutaneous tumours but not to brain tumours. In contrast with other hamster brain tumours induced by human adenovirus type 12 or human papova JC virus, medulloepithelioma or medulloblastoma, SA-7 induced tumours exhibit distinctive histological and localization characteristics.