Maria Benevolo

Extended HPV genotyping by the BD Onclarity assay: concordance with screening HPV-DNA assays, triage biomarkers, and histopathology in women from the NTCC2 study

ABSTRACT The use of clinically validated human papillomavirus (HPV) assays is recommended in cervical cancer screening, and extended genotyping is getting attention as a triage biomarker because of the different oncogenic risk of the high-risk HPV genotypes. We compared the results of the Becton & Dickinson (BD) Onclarity HPV assay, on the residual baseline cervico-vaginal specimens of the NTCC2 trial, to those of the screening HPV-DNA assay (Cobas 4800 or HC2) and to cytology, p16/ki67 and E6/E7 mRNA triage results. We genotyped virtually all HPV-positive women and a consecutive sample of HPV-negatives. Among the 3,129 baseline-positives, 75.5% ( k = 0.368) were BD-positive, as were 5 of the 333 baseline-negatives (1.5%). The concordance between BD and HPV-DNA screening test was 87% for Cobas (1,250/1,436) and 65.9% for HC2 (1,115/1,693). A higher than the recommended positivity threshold for Onclarity would increase the agreement but would not improve concordance in the overall screening population. Among the baseline-positive cases, we observed an increasing trend of BD positivity with cytology severity (from 71.6% in negative for intraepithelial lesion of malignancy to 95.1% in ASC-H+ samples), with histologically confirmed CIN3 (96.9%), with p16/ki67 dual staining positivity (90.9% among the positive and 69.6% among the negative specimens), and with E6/E7 mRNA positivity (93.4% in the mRNA-positive cases vs 39.7% among the mRNA-negatives). Our findings confirm some disagreement among different HPV assays used for screening. Nevertheless, the agreement is substantial for women with high-grade cytology, histologically confirmed CIN3, and p16/ki67 or mRNA positivity at triage, thus confirming a good clinical performance of all the tests used. The NTCC2 trial is registered as Clinicaltrials.gov identifier NCT01837693 . IMPORTANCE Large randomized clinical trials have demonstrated that human papillomavirus (HPV) testing for high-risk types is more effective than cytology in detecting pre-cancerous lesions and preventing cervical cancer. Its use is being implemented in cervical cancer screening in several countries. The most recent guidelines recommend a risk-based management. It is therefore important to assess the individual risk of having/developing high-grade lesions of women testing high-risk HPV-positive. A crucial viral factor influencing the risk is the HPV genotype since different types are associated to different carcinogenetic risks. Understanding the degree of concordance among different assays targeting either HPV presence/type(s) or cellular morphology and proteins’ expression provides knowledge useful to better define how these tests can be used in screening protocols for an effective triage and to anticipate the possible implementation issues. Our study shows that the concordance between tests is higher when the infections have a higher probability of producing a clinically relevant lesion.

Comparison of HPV-positive triage strategies combining extended genotyping with cytology or p16/ki67 dual staining in the Italian NTCC2 study

Each high-risk HPV genotype has different oncogenic potential, and the risk of CIN3+ varies according to genotype. We evaluated the performance of different strategies of HPV-positivity triage combining cytology, p16/ki67 dual staining (DS), and extended genotyping. Samples from 3180 consecutive women from the NTCC2 study (NCT01837693) positive for HPV DNA at primary screening, were retrospectively analyzed by the BD Onclarity HPV Assay, which allows extended genotyping. Genotypes were divided into three groups based on the risk of CIN3+. HPV DNA-positive women were followed up for 24 months or to clearance. Combining the three groups of genotypes with cytology or DS results we identify a group of women who need immediate colposcopy (PPV for CIN3+ from 7.8 to 20.1%), a group that can be referred to 1-year HPV retesting (PPV in those HPV-positive at retesting from 2.2 to 3.8), and a group with a very low 24-month CIN3+ risk, i.e. 0.4%, composed by women cytology or DS negative and positive for HPV 56/59/66 or 35/39/68 or negative with the Onclarity test, who can be referred to 3-year retesting. Among the baseline HPV DNA positive/cytology or DS negative women, the extended genotyping allows to stratify for risk of CIN3+, and to identify a group of women with a risk of CIN3+ so low in the next 24 months that they could be referred to a new screening round after 3 years. Italian Ministry of Health (grant number RF-2009-1536040). Hologic-Genprobe, Roche Diagnostics, and Becton & Dickinson provided financial and non-financial support.