SV40 in childhood lymphoma – pathogen or passenger?

Simian Virus 40 (SV40), a potent oncogenic virus, has been prior associated with some human cancer, also with lymphomas. Its oncogenic potential is based on the large T-antigen (TAG). Very different findings as well as the lack of control groups in most reports make it difficult to assess the SV40-lymphoma association.

We analysed 31 DNA's derived from bone marrow (BM) or pripheral blood (PBL) of 19 B-ALL, 7 BCP-ALL, 5 T-ALL, for the presence of SV40-TAG seqences by RQ-PCR and PCR. Overall 24 of them showed SV40 in various amounts. In 11 cases SV40 was detectable at diagnosis as well as at the end of therapy in equal amounts. Two patients show SV40 in BM, but not in PBL at diagnosis. Two cell lines, SV80 (episomal) and COS-7 (integrated) served as positive controls. (SV80 was used as SV40-standard in case of quantification.) Only 2 out of 149 DNA's from buffy coat of a healthy control group showed SV40, while SV40 was detectable in all 25 BM donations, taken from healthy family members of children with diverse lymphoproliferative disorders. Taken together SV40 seems to be more present in BM than in PBL and was not eliminated during therapy. The question whether SV40 is a pathogen or a passenger has to be answered by additional analysis. Nevertheless the overall incidence of 24 SV40+ out of 31 childhood lymphomas, might support evidence, that this virus could be connected with this disease.