Absence of papillomavirus DNA in normal tissue adjacent to most cervical intraepithelial neoplasms

To determine if human papillomavirus (HPV) DNA is present in the normal mucosa adjacent to cervical intraepithelial neoplasia (CIN).

Serial sections of 28 CIN lesions were studied. Lesional and normal epithelia and stroma were microdissected; the DNA was extracted and amplified by polymerase chain reaction (PCR) using primers designed to amplify both HPV late (L1) and human beta-globin sequences. Human papillomavirus was typed by restriction fragment length polymorphism analysis following digestion of PCR products.

Twenty-five of 28 (89%) lesional epithelia scored positive for HPV nucleic acids. In' four of 25 (16%) HPV-positives, the normal squamous epithelium scored positive for HPV nucleic acids, two of which (8%) also scored positive in the stroma. Repeat microdissection and PCR analysis of three of these cases was performed and all were negative in both normal epithelium and stroma, suggesting laboratory contamination.

Human papillomavirus nucleic acids are present uncommonly in normal-appearing squamous epithelium adjacent to CIN. This does not exclude occult infection in the natural history of CIN but indicates that when lesions develop, occult infection is not normally maintained in the normal mucosa. This is consistent with the low recurrence rates following ablation as well as low indices of HPV positivity in normal cervices during follow-up. This finding should be taken into consideration when counseling patients and is relevant to the concept of HPV testing during follow-up after cone biopsy.