Analysis of human cancers,normal tissues,and verruce plantares for DNA sequences of human papillomavirus types 1 and 2

Comparatively little is known about human papillomaviruses (HPV) because they cannot be grown in tissue culture. We have in vitro labeled DNAs from two HPVs, HPV-1 which was isolated from plantar warts, and HPV-2 which was isolated from common hand warts, and used these DNAs to examine the homology between HPV-1 and HPV-2, to examine the state of the HPV genome in papillomavirus lesions, and to assay human cancer DNAs for HPV. The specific activities of the DNAs were 5.0 × 10⁷ to 1.1 × 10⁸ cpm/μg. The $\text{C}{}_0\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ of the HPV-1 and HPV-2 DNAs were 5 and 7 × 10^?4, respectively, consistent with a genome molecular weight of about 5.2 × 10⁶. Cross-hybridization of HPV-1 and HPV-2 DNAs revealed only 5–7% homology, confirming that these are distinct viruses. HPV-1 DNA was detected by Southern blot analysis in 9 of 10 plantar warts examined. No clear evidence was found for integrated viral sequences in DNAs from eight of the nine warts analyzed. Using these HPV-1 and HPV-2 probes, we have performed the first extensive and definitive molecular hybridization analysis of human cancer DNAs for HPV sequences. Human tumor DNAs were analyzed for HPV sequences by saturation hybridization using nick-translated HPV-1 and HPV-2 DNA probes. Reconstruction experiments with added HPV-1 or HPV-2 DNAs indicated that the probes could detect 0.1 copy of the viral genome per diploid equivalent of cellular DNA. No HPV-1 sequences were detected in DNAs from 156 human cancers (14 melanoma, 3 Ca skin, 5 Ca pharynx, 1 Ca esophagus, 4 Ca stomach, 5 Ca small intestine, 22 Ca colon, 14 Ca rectum, 25 squamous cell Ca lung, 3 adenocarcinoma lung, 4 oat cell Ca lung, 21 Ca kidney, 7 Ca bladder, 3 Ca ovary, 3 Ca cervix, 4 Ca prostate, 10 non-Hodgkin lymphoma, 2 reticulum cell sarcoma spleen]), or 27 normal human tissues (1 skin, 10 tonsil, 8 colon, 8 kidney). No HPV-2 sequences were detected in DNAs from 145 human cancers (13 melanoma, 4 Ca skin, 2 Ca pharynx, 3 Ca mouth, 7 Ca esophagus, 4 Ca stomach, 3 Ca small intestine, 29 Ca colon, 15 Ca rectum, 25 Ca kidney, 15 Ca bladder, 2 Ca ovary, 6 Ca cervix, 4 Ca prostate, 2 Ca seminoma testes, 11 non-Hodgkin lymphoma) or 1 normal human ovary. These data are strong evidence that none of the cancer specimens assayed were induced by HPV-1 or HPV-2. However, additional work is required to fully evaluate whether HPVs are possible agents of human cancers, because the cancer types assayed in this study represent only about 50% of the cancer incidence in the United States, and because our probes would not detect sequences of other recognized HPV types (HPV-3, HPV-4, and HPV-5).