Detection of human papillomavirus type 16 in microtitre plate based immuno-enzymatic assays: Use to determine E5 gene expression in cervical carcinomas

Background: E5-based nested polymerase chain reaction (PCR) assays and a PCR-enzyme immunoassay (EIA) to detect human papillomavirus type 16 (HPV-16) DNA have been developed. These assays were designed to detect small amounts of HPV-16 DNA for epidemiological studies of subclinical infection. Objectives: The E5 gene of HPV-16 may be lost in some cell lines derived from cervical carcinomas. The aim of this study was to determine if, and how frequently, E5 gene loss occurs in biopsy samples from patients with cervical lesions. Study design: Sixteen HPV-16 (E7) DNA positive and five HPV-16 DNA negative cervical lesions (nineteen cervical carcinomas, two cervical intraepithelial neoplasias) were investigated by E5 nested PCR and EIA. Results: Overall, 15 of the 16 (93.75%) HPV-16 E7 positive samples were positive for HPV-16 E5 DNA: 14 of 16 (87.5%) were positive by E5 PCR and 15 of 16 (93.75%) were positive by E5 PCR, nested PCR and by PCR-EIA. One of 14 HPV-1B (E7) DNA positive cervical carcinomas was negative for E5 DNA in all three assays. Conclusion: Loss of the HPV-16 E5 open reading frame (ORF) is a rare event in HPV-16 positive cervical carcinomas and was detected in just one of 14 (7.1%) cases.