DNA-SEQUENCES SIMILAR TO THOSE OF SIMIAN VIRUS-40 IN EPENDYMOMAS AND CHOROID-PLEXUS TUMORS OF CHILDHOOD

Background. Ependymomas and papillomas of the choroid plexus occur in early childhood. The ubiquitous human polyomaviruses, BK virus and JC virus, have been associated with the induction of these neoplasms in a nimal models. A related monkey polyomavirus, simian virus 40 (SV40), i s highly tumorigenic in rodents and also induces choroid plexus papill omas. Methods. We tested the possibility that polyomaviruses were asso ciated with these tumors in humans. Tumors from 31 children - 20 with choroid plexus neoplasms and 11 with ependymomas - were evaluated for the presence of polyomavirus T-antigen gene sequences by means of ampl ification with the polymerase chain reaction. Results. Ten of the 2O c horoid plexus tumors and 10 of the 11 ependymomas contained amplificat ion products that preferentially hybridized to probes specific for SV4 0 viral DNA rather than BK or JC viral DNA. In two specimens, DNA sequ encing demonstrated that the amplified sequence was identical to the s equence of that region of the SV40 gene. In three other specimens, amp lification with SV40-specific primers revealed a 574-bp segment of the SV40 viral gene. In 7 of 11 tumors examined by immunohistochemical st aining, viral T antigen was expressed in the nuclei of the neoplastic cells. Conclusions. Half of the choroid plexus tumors and most of the ependymomas that we studied contained and expressed a segment of T-ant igen gene related to SV40. These results suggest that SV40 or a closel y related virus may have an etiologic role in the development of these neoplasms during childhood, as in animal models.