Detection of high-risk human papillomavirus E6 and E7 oncogene transcripts in cervical scrapes by nested RT-polymerase chain reaction.
The oncogenic potential of the high-risk human papillomavirus (HPV) genotypes (types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68) depends on the expression of the two viral oncogenes E6 and E7. Thus, the detection of HPV E6/E7 oncogene transcripts could serve as a factor in the evaluation of a risk of development of cervical intraepithelial neoplasia (CIN) and its progression to cervical cancer. A nested RT-PCR assay for the detection of E6/E7 oncogene transcripts of all known high-risk HPV genotypes was established. In the study described, 779 high-risk HPV-DNA-positive cervical scrapes exhibiting all grades of CIN, including non-dysplastic cervical mucosa (CIN 0), were examined. Spliced E6/E7 oncogene transcripts of all the high-risk HPVs were detected in numerous samples, with an overall detection rate of 47%. In 227 cases with agreement between the cytologic and histologic findings, the prevalence increased with lesion severity: CIN 0, 18%; CIN I, 58%; CIN II, 77%; CIN III, 84%. Multiple transcriptionally active high-risk HPVs were detected in 12% (33/279) of patients with multiple high-risk HPV infections. This work sets the stage for a prospective follow-up study currently being undertaken to evaluate the prognostic relevance of the detection of high-risk HPV E6/E7 oncogene transcripts for the persistence of a high risk HPV infection, and the possible evolution and further development of a CIN. Future applications of the assay described may include the monitoring of women in studies investigating antiviral treatment or vaccination.