Detection of specific human papillomavirus types in paraffin-embedded sections of cervical carcinomas

Human papillomaviruses (HPV) are the causative agents of most cervical carcinomas. A complete understanding of the HPV types that cause cervical carcinoma is needed as vaccines are designed. Fresh tissues are not always available for such studies. We therefore sought to determine the feasibility of HPV studies using formalin-fixed, paraffin-embedded sections of 56 cervical carcinomas, correlating typing information with the pathology and physical state of the HPV sequences within cells. Sections from each specimen were used to extract and purify DNA. Specific HPV types were identified using a PCR/reverse blot strip assay. Tyramide signal-amplified, fluorescent DNA in situ hybridization (FISH) was used to localize HPV within cells. Human beta-globin sequences were amplified in DNA from all specimens. HPV sequences from oncogenic types were identified in 52 of 56 (92.9%) by PCR/reverse blot strip assay, and in one additional case using an HPV 16 multiplex PCR assay. HPV 16 was the most commonly detected type, present in most cases as a solitary isolate. Thirty- five of 42 HPV 16 or HPV 18 PCR-positive specimens were also positive in the FISH assay, in most cases in a pattern consistent with viral integration. We conclude that HPV typing from formalin-fixed, paraffin-embedded sections of cervical carcinomas is possible, with a sensitivity that is similar to that found in studies using fresh tissue.