Isolation of a new type of human papillomavirus (HPV52b) with a transforming activity from cervical cancer tissue

Substantial evidence has implicated human papillomaviruses (HPVs) as etiological agents of human cervical cancer. We detected and cloned an unidentified HPV genome in cellular DNA extracted from a surgical specimen of a Japanese patient with cervical cancer. Hybridization studies suggested that this HPV was the most homologous to HPV33 among more than 51 types of HPV ever identified. A recently identified new HPV, isolated by W. Lancaster and designated HPV52, is also most homologous to HPV33 (W. Lancaster et al. , unpublished data). Our HPV was found to be homologous but not identical to HPV52 and hence was designated HPV52b. By introducing it into NIH3T3 cells, we found that HPV52b DNA had growth-stimulating activity as HPV16 DNA. This newly identified HPV52b DNA was present as episomes in cervical cancer cells of two out of two specimens so far examined and the integrated copies were not detected. HPV52b was present in three out of 15 (20%) specimens in Japan. In addition, the presence of three additional unidentified HPV sequences homologous to HPV52b was detected in three other specimens. The results suggest that this group of HPV may be prevalent and involved in carcinogenesis of cervical cancer in Japan.