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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 animal models. A related monkey polyomavirus, simian virus 40 (SV40), is highly tumorigenic in rodents and also induces choroid plexus papillomas.

Methods. We tested the possibility that polyomaviruses were associated 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 amplification with the polymerase chain reaction.

Results. Ten of the 20 choroid plexus tumors and 10 of the 11 ependymomas contained amplification products that preferentially hybridized to probes specific for SV40 viral DNA rather than BK or JC viral DNA. In two specimens, DNA sequencing demonstrated that the amplified sequence was identical to the sequence of that region of the SV40 gene. In three other specimens, amplification with SV40-specific primers revealed a 574-bp segment of the SV40 viral gene. In 7 of 11 tumors examined by immunohistochemical staining, 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-antigen gene related to SV40. These results suggest that SV40 or a closely related virus may have an etiologic role in the development of these neoplasms during childhood, as in animal models. (N Engl J Med 1992;326:988-93.)

EPIDEMIOLOGIC studies have shown that 70 to 80 percent of adults are seropositive for the human polyomaviruses BK and JC. 1,2 BK virus, originally discovered in the urine of a renal-transplant recipient,3 is thought to be a cause of hemorrhagic cystitis and nephritis in immunosuppressed patients. JC virus, which infects oligodendrocytes, has been linked with progressive multifocal leukoencephalopathy.4 Both viruses are presumably acquired as primary infections in childhood, and they persist benignly in the immunocompetent host. The monkey polyomavirus simian virus 40 (SV40), a potent virus that induces tumors in laboratory animals, was found to be a contaminant of polio vaccines [horizontal ellipsis]

Owned, published, and (C) copyrighted, 1992, by the MASSACHUSETTS MEDICAL SOCIETY