Human papillomavirus (HPV) is the only DNA tumour virus where a large body of evidence implicates it in human cancers. The evidence for a causative role of HPV in human cervical cancer, was recently reviewed by zur Hausen,¹ and is the following: (1) expression of specific HPV genes (such as E6 and E7) were shown in cervical cancer cell lines and cancer biopsies²; (2) viral DNA was shown to have immortalisation properties^3,4; (3) viral oncogene expression was shown to be required for the maintenance of the malignant phenotype in specific cervical cancer cell lines^5,6; (4) a substantial number of epidemiological studies have been performed which point to high risk HPV as a primary risk factor for cervical cancer. In addition, large case-control and prospective epidemiological studies supported this idea, and indicated that persisting HPV infections were the most significant risk factor in cervical cancer.^7,8

Different types of HPV have been identified in a high percentage of non-melanoma skin cancers …