OC 08-11HPV E7 ONCOPROTEIN-BASED ELISA ASSAY FOR TRIAGE OF HPV-POSITIVELY SCREENED WOMEN

08. Screening methods
T. Agorastos 1, K. Chatzistamatiou 1, I. Hagemann 2, E. Boschetti 3, O. Boecher 4, I. Koch 4, E. Soutschek 4, I. Lekka 5, A. Skenderi 6, E. Aggelis 6, H. Pircher 7, P. Jansen-Duerr 7, A.M. Kaufmann 3.
14th Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Hippokratio General Hospital, Thessaloniki, Greece (Greece), 2MVZ Im Mare, Kiel (Germany), 3Clinic for Gynecology, Charité-Universtitaetsmedizin Berlin, Campus Benjamin Franklin, Berlin (Germany), 4Mikrogen GmbH, Munich (Germany), 5Laboratory of Bioinformatics, Department of Medicine, Aristotle University of Thessaloniki, Thessaloniki (Greece), 6Laboratory of Cytology, Hippokratio General Hospital, Thessaloniki (Greece), 7Research Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck (Austria)

Background / Objectives

Persistent infection of papillomaviruses (PIPAVIR) high-risk (hr) types is a prerequisite for the development of cervical dysplasia. Expression of oncoproteins E6 and E7 and their upregulation during progression is associated with loss of cell cycle control and cellular neoplastic transformation. New high-affinity rabMab antibodies have been developed for detection of E7 of 12 most prevalent hr-HPV types in an ELISA format. Primary HPV screening by highly sensitive methods detecting HPV nucleic acids needs efficient triaging. A molecular test detecting hrE7 with comparable specificity to cytology could be advantageous. A clinical trial was performed to generate first data on applicability and sensitivity/specificity of a hrE7-based ELISA.


Methods

PreserveCyte cervical samples  (1258) were collected. Cytological samples were prepared and all women got expert colposcopy and biopsy if indicated. Multiplexed genotyping was performed. From the same smear hrE7 ELISA was performed. Different hrE7 ELISA formats were used detecting HPV 16/18/31/33/35/39/45/51/52/56/58/59 (recomWell HPV HR screen); HPV16/31/33/35/52/58 (recomWell HPV plus); or HPV16/18/45 (recomWell HPV 16/18/45) and results correlated to histological findings. Thresholds, sensitivity, specificity, PPV, NPV for detection of CIN2+ were calculated and compared against HPV test and cytology.


Results

HPV testing by MPG had by definition a sensitivity of 100% (25/25) in detecting CIN2+ in a triage setting considering all hr-HPV positives (n=269). PPV was only 9.29%. Sensitivity of cytology as triage for HPV-positive women to colposcopy was 52% (13/25) and specificity 85% (208/244), PPV was 26.5% and NPV 94.5%. hrE7 ELISA as triage was performed in the different formats. Detection by recomWell HPV HR screen, recomWell HPV plus, and recomWell HPV 16/18/45 had sensitivity of 92%, 76%, 72%; a specificity of 43%, 72%, 71%; a PPV of 14.2%, 22.1%, 20.5, and NPV of 98.1%, 96.7%, 96.1%, respectively.


Conclusion

A molecular triage of hrHPV positive screening results would have technical advantage over PAP cytological triage and could be performed as reflex testing, especially on HPV16 or 18 positive women. Triaging hrHPV DNA positive women for detection of CIN2+ by cytology has slightly better performance than E7 testing in terms of PPV. hrE7 ELISA testing showed higher sensitivity than cytology. RecomWell HPV plus had similar PPV and sensitivity as cytology. All hrE7-ELISA formats have shown higher sensitivity and comparable specificity, PPV and NPV as compared to cytology in detection of CIN2+ dysplasia. Therefore, the new hrE7-ELISA could be viewed as an alternative test to cytology in triaging hrHPV positively tested women.


References