[Biology of epidermodysplasia verruciformis-associated HPV]

The genus betapapillomavirus (betaPV) presently comprises more than 40 virus types including the so-called epidermodysplasia verruciformis (EV)-associated HPV, which were originally detected in EV-patients by Southern blot hybridization. BetaPV are ubiquitous in the general population and frequently establish themselves already during the first weeks of life. Hair follicles are regarded as natural reservoir. About 25% of betaPV detected in adults persist for at least 9 months. Due to very low virus production, seroconversion against betaPV starts sluggishly. Hyperproliferation of keratinocytes in psoriasis patients or after severe burns stimulates virus replication. Massive virus replication only occurs in EV-patients, associated with the induction of disseminated skin lesions with a high risk of malignant conversion. In 75% of EV-patients this can be put down to homozygous, inactivating mutations in the genes EVER1 or EVER2. A transgenic mouse model substantiated the crucial role of increased HPV8 oncogene expression, induced by UV-irradiation or wounding, for tumor induction.