Predictive testing of early cervical pre-cancer by detecting human papillomavirus E6/E7 mRNA in cervical cytologies up to high-grade squamous intraepithelial lesions: Diagnostic and prognostic implications

The type-specific persistence of oncogenic human papillomavirus (HPV) is considered to be the true precursor of cervical cancer at which the transcription of the viral oncogenes E6 and E7 is necessary for the malignant transformation and maintenance of the neoplastic state. In the present pilot study, a cohort of 66 women was investigated from a routine office-based screening population who had an index cytological result from normal to high-grade squamous intraepithelial lesions and who were also HPV-DNA positive for at least one of the following high-risk HPV types: HPV 16, 18, 31, 33 and 45 detected by MY09/MY11 consensus and GP5+/6+ general primers, followed by sequencing. The expression of E6/E7 transcripts from the same HPV types was detected by the PreTect HPV-Proofer. Cervical status was checked 18 months after the mRNA test. The expression of E6/E7 mRNA was found in 58% of the cases showing a 97% concordance with the HPV-DNA types and a positive correlation with increasing cytological and histological grade. All HPV-mRNA positive cases were also positive for HPV DNA whereas 25 (38%) of the HPV-DNA positive cases did not express the respective mRNA. The diagnostic validity of the PreTect assay for detecting histologically-proven prevalent CIN3 lesions were: sensitivity 95%, specificity 55%, positive predictive value (PPV) 81% and negative predictive value (NPV) 86%. The prognostic power of the PreTect test for predicting cytological disease progression was as follows: 78% sensitivity, 60% specificity, 37% PPV and 90% NPV. In conclusion, our results showed that the detection of oncogenic HPV E6/E7 mRNA in cervical smears in a routine screening setting identifies prevalent CIN3 lesions with nearly 100% sensitivity and has a very high negative predictive value for disease progression during the natural course of HPV infection. Thus, testing for HPV oncogenic activity may be used as a clinically predictive marker to enhance the net effectiveness of screening and enable the prognostication of prevalent cervical lesions.