As reference sequences, the following GenBank accession number were used: HBoV-1=FJ858259(Bonn-1) a. aligned PCR product sequences obtained from tumor tissue samples. In total, 15 samples had enough DNA present after PCR amplification for direct sequencing. Sequences were blasted and aligned to the reference strain Bonn-1. It is obvious that all sequences were highly conserved and fully matched the reference sequence. Three sequences had additional non-HBoV sequence upstream of the aligned regions (shown in Figure 1b). b. Alignment of the upstream sequence present in three HBoV genomes isolated from tumor tissues. The upstream inserted sequence was observed in three samples that were independently DNA-extracted and analyzed by PCR and sequencing in three independent runs, thus excluding a single artifact or cross contamination event. Surprisingly, the underlined sequences fully matched the human DNA sequence from chromosome 5, reference sequences AC008698.6 (Homo sapiens chromosome 5 clone CTB-70H11, bases 76065-76026) and AC025156.2 (Homo sapiens 3 BAC RP11-494C5 from Roswell Park Cancer Institute, bases 130245-130284), indicating that HBoV is able to recombine with its host.