The detection of human papillomaviruses in cervical biopsies by immunohistochemistry and in situ hybridization.

The presence of human papillomavirus (HPV) types 6, 16 and 18 in cervical biopsies can be detected by an immunoperoxidase technique using type-restricted monoclonal antibodies raised against fusion proteins representing the L1 major capsid proteins of these three HPV types. In a retrospective study (n = 54) we have used these antibodies and biotinylated DNA probes of HPV 6, 16 and 18 to detect and type HPV in formalin-fixed material from the cervix. The biopsies were classified histologically into normals, wart infections without dysplasia, cervical intraepithelial neoplasia (CIN) and squamous cell carcinomas. Antibody staining showed that 22% of all CIN was positive for HPV 16 and 40% of cervical warts were positive for HPV 6, 16 and 18. There was no HPV capsid protein detected in the normals and squamous cell carcinomas using these antibodies, whereas 25% of the tumours were positive for HPV 16 by in situ hybridization. Sections of cervical warts and CIN positive for HPV types by in situ hybridization were also positive by antibody staining which suggests that both techniques are detecting replicating virus. We feel these two techniques complement each other in detection and typing of HPV in cervical biopsies from patients with active disease.