Screening human tumor samples with a broad-spectrum polymerase chain reaction method for the detection of polyomaviruses.

Polyomaviruses induce tumors of different histological types when inoculated into experimental animals. An etiological role for this virus group in the development of malignant tumors in humans remains questionable, despite several reports demonstrating the presence of SV40, JCV, and BKV DNA in human cancers. Only two human polyomavirus types are known to date: JCV, causing progressive multifocal leukoencephalopathy (PML) under severe immunosuppression, and BKV, first isolated from the urine of a renal transplant recipient and associated with hemorrhagic cystitis. We developed a degenerate polymerase chain reaction assay in an attempt to identify additional, presently unknown human polyomavirus types that may be involved in the malignant transformation of human tissues. A large part of the gene coding for the viral capsid protein VP1 is highly conserved in nine polyomavirus types (and their strains) and was therefore selected as most suitable for the primer design. Degenerate oligonucleotide primers were deduced from four different conserved amino acid motifs in this region. Three different sets of primers were included in each test to obtain the highest sensitivity in combination with primers with the lowest degeneracy numbers. The sensitivity obtained ranged from 1 copy/cell for bovine polyomavirus to 100 copies/cell for LPV after ethidium bromide staining and was increased at least 10-fold after hybridization with a radiolabeled probe. A subsequent seminested amplification allowed for the detection of 1 copy/cell for LPV. These degenerate primers were applied to analyze bladder carcinomas, Hodgkin lymphomas, meningiomas, Kaposi tumors, and Kaposi-derived cell lines. No polyomavirus DNA sequences could be detected.