Evidence of HPV16 integration in low- and high-grade cervical lesions that regress demonstrated by multiple displacement amplification and Southern blot hybridisation.

The prevalence and significance of human papillomavirus (HPV) integration among different grades of cervical lesions is uncertain. In this study, HPV physical status was examined by the combination of multiple displacement amplification (MDA) with Southern blot hybridisation (SBH). DNA extracts from 95 cervical cytology samples (NILM, ASC-US, LSIL, ASC-H, HSIL) were subject to whole genome amplification by MDA followed by SBH with [alpha-(32)P]-labelled HPV probes. Mixed HPV16 episomal/integrant sequences were detected in three ASC-US patients (two diagnosed with benign changes and one with cervical intraepithelial neoplasia (CIN)2/3 after biopsy follow-up), one ASC-H patient with CIN2/3 histological diagnosis, and one HSIL patient with benign changes. Additional follow-up cytological data available for three of these patients demonstrated series of lesion-free samples. The data support the view that integration can occur in low-grade lesions and that lesions with mixed episomal/integrant HPV can regress.