Demonstration of URR-duplication variants of human papillomavirus type 6 in paraffin-embedded tissue sections of one condyloma acuminatum and one Buschke-Loewenstein tumour.

Human papillomavirus type 6 (HPV 6) induces condylomata acuminata and laryngeal papillomas. Occasionally, HPV 6 may also be found in low-grade verrucous carcinomas. In some tumours, genetic analysis revealed the presence of HPV 6 variants with rearrangements, mostly DNA duplications, within the upstream regulatory region (URR). In this study, we analysed 98 formalin-fixed, paraffin-embedded condylomata acuminata obtained from 54 patients for the presence of URR-duplication variants of HPV 6. HPV 6 DNA could be amplified by polymerase chain reaction (PCR) from 40 samples. One condyloma acuminatum contained a HPV 6 genome with rearranged URR. Analysis using restriction enzyme cleavage suggested a DNA duplication within the URR of approximately 200 bp, spanning the Hpa II site at nt 7863 and the Dde I site at nt 7843 but not involving the Rsa I site at nt 7633. In addition, we analysed the distribution of the already characterized URR-duplication variant HPV 6AC1B within different paraffin-embedded tissue sections of a Buschke-Loewenstein tumour. No correlation could be demonstrated between the presence of the rearranged genome and malignant histological changes. This result and the demonstration of an URR-duplication variant in a typical condyloma acuminatum suggest that duplications within the URR of HPV 6 are not directly related to malignant progression of HPV 6-induced tumours.