1. ¹Institute for Clinical Science, Division of Obstetrics and Gynaecology, Karolinska University Hospital, Huddinge, Karolinska Institute, 141 86 Stockholm, Sweden
2. ²Division of Clinical Virology, Department of Laboratory Medicine, Karolinska University Hospital at Huddinge, Karolinska Institute, 141 86 Stockholm, Sweden
3. ³Department of Genetics and Pathology, Section of Medical Genetics, Rudbeck Laboratory, University of Uppsala, 751 85 Uppsala, Sweden

Correspondence: Dr S Andersson, E-mail: sonia.andersson@telia.com

Received 20 January 2005; Revised 18 April 2005; Accepted 27 April 2005; Published online 7 June 2005.

Abstract

A series of 176 archival cervical intraepithelial neoplasia (CIN) was analysed for the presence, viral load and integration status of 'high-risk' types of human papillomavirus (HR-HPV). The samples were assayed using newly developed methods based on real-time PCR. Two methods for the extraction of DNA from the paraffin-embedded biopsies were compared: a protocol based on the MagNA pure system (Roche) and a Qiagen spin column kit (Qiagen). It was possible to amplify 94% (166) of the samples. Of these, 36, 63 and 80% of the CIN I, II and III cases contained HR-HPV. HPV 16 was the most prevalent, and was found in 20, 28 and 46% of the CIN I, II and III cases, respectively. The second most frequent HR-HPV was type 33 group, and in CIN II it was as prevalent as HPV 16. The median number of copies of HR-HPV per cell was not significantly different in the CIN I, II and III cases, but there was a wide range of viral load values over several magnitudes, regardless of the grade of CIN. All samples were found to contain integrated forms of HPV 16, frequently mixed with an episomal form.