Evaluation of CIN2/3 Lesion Regression in GynTect® DNA Methylation-Marker-Negative Patients in a Longitudinal Study.

Cervical intraepithelial neoplasia (CIN) grade 2/3 has a high spontaneous regression rate, especially among women ≤29 years of age. To reduce overtreatment, reliable prognostic biomarkers would be helpful. The main aim of this study was to analyze the negative predictive value of the methylation marker panel GynTect® for lesion regression. In this prospective, multicenter, longitudinal observational proof-of-concept study, women aged ≤29 years with histologically confirmed CIN2 (n = 24) or CIN3 (n = 36) were closely monitored without treatment for up to 24 or 12 months, respectively. The outcome was either regression, persistence, or progression of the lesion. For each patient, a single baseline sample (V0) for cytology, hrHPV detection and methylation analysis was taken. In a primary analysis, the negative predictive value (NPV) of a GynTect®-negative test result at V0 for regression was determined. We tested the null hypothesis NPV ≤ 70% against the alternative hypothesis NPV ≥ 90%. Twelve of the eighteen GynTect®-negative CIN2 patients showed regression (NPV = 67%, 90% CI 44-85%, p = 0.53). Of the 27 GynTect®-negative CIN3 lesions, 15 regressed (NPV = 56%, 90% CI 38-72%, p = 0.92). Although the majority of GynTect®-negative lesions regressed, the postulated NPV of ≥90% was not observed. Thus, the clinical relevance for an implementation of the GynTect® assay for patients undergoing watchful waiting remains questionable. Further studies with longer observation periods should be undertaken.

Triage of hrHPV-positive women: comparison of two commercial methylation-specific PCR assays.

AIM: High-risk human papillomavirus (hrHPV)-based screening is becoming increasingly important, either by supplementing or replacing the traditional cytology-based cervical Pap smear. However, hrHPV screening lacks specificity, because it cannot differentiate between transient virus infection and clinically relevant hrHPV-induced disease. Therefore, reliable triage methods are needed for the identification of HPV-positive women with cervical intraepithelial neoplasia (CIN) in need of treatment. Promising tools discussed for the triage of these patients are molecular diagnostic tests based on epigenetic markers. Here, we compare the performance of two commercially available DNA methylation-based diagnostic assays-GynTect® and the QIAsure Methylation Test-in physician-taken cervical scrapes from 195 subjects. FINDINGS: Both GynTect® and the QIAsure Methylation Test detected all cervical carcinoma and carcinoma in situ (CIS). The differences observed in the detection rates between both assays for the different grades of cervical lesions (QIAsure Methylation Test: CIN1 26.7%, CIN2 27.8% and CIN3 74.3%; GynTect®: CIN1 13.3%, CIN2 33.3% and CIN3 60%) were not significant. Concerning the false-positive rates, significant differences were evident. For the healthy (NILM) hrHPV-positive group, the false-positive rates were 5.7% for GynTect® and 26.4% for QIAsure Methylation Test (p = 0.003) and for the NILM hrHPV-negative group 2.2% vs. 23.9% (p = 0.006), respectively. When considering hrHPV-positive samples only for comparison (n = 149), GynTect® delivered significantly higher specificity compared to the QIAsure Methylation Test for CIN2 + (87.6% vs. 67.4% (p < 0.001)) and CIN3 + (84.1% vs. 68.2% (p = 0.002)). Overall our findings suggest that DNA methylation-based tests are suitable for the triage of hrHPV-positive women. With the goal to provide a triage test that complements the limited specificity of HPV testing in HPV-based screening, GynTect® may be preferable, due to its higher specificity for CIN2+ or CIN3+ .

Combined assessment of 3q26 amplification and promoter methylation in patients with high grade cervical lesions show age specific differences.

A considerable proportion of high grade cervical intraepithelial lesions (CIN2/3) are known to resolve on their own especially among young women. However, since reliable prognostic markers are still lacking, the diagnosis "CIN3" is still an indication for surgery which may result in overtreatment. It is conceivable that a combination of different, ideally independent molecular markers may provide more reliable results. In the present cross-sectional study two established triage markers, 3q26 amplification and a methylation signature, were evaluated in an age-dependent manner. The patient cohort comprised 60 patients with histologically confirmed CIN2/3 in two equally sized age groups (<30 years, ≥30 years). Cervical scrapes were analyzed by interphase fluorescence in situ hybridization for 3q26 amplification and methylation specific PCR (GynTect®) for six different genome regions. Both assays showed a significantly different pattern of test outcome independent of age (P = .001). Moreover, the combination of both assays differed significantly for double positive and double negative cases when comparing the two age groups: In patients <30 years there were clearly less cases with positive methylation signature and amplification of 3q26 as in women ≥30 years (23% vs 63%, Bonferroni adjusted P = .016). Of particular interest is the finding that double negative results were exclusive for the young age group (0% vs 27%, Bonferroni adjusted P = .020). Since regression of CIN2/3 characteristically occurs among young women it is tempting to speculate that a double negative test result could be prognostic for regression of CIN2/3. This will have to be investigated further in a prospective longitudinal intervention study.

Performance of a methylation specific real-time PCR assay as a triage test for HPV-positive women.

BACKGROUND: HPV DNA testing as a primary screening marker is being implemented in several countries. Due to the high HPV prevalence in the screening population, effective triage strategies for HPV-positive cases are required. The aim of this study was to evaluate the performance of a methylation-specific real-time PCR  assay (GynTect®) comprising six marker regions as a triage test. RESULTS: An analytical sensitivity of 0.1 ng genomic DNA corresponding to 15 SiHa cells was achieved. Absolute specificity was observed in the presence of 20 ng unmethylated genomic DNA. In a clinical setting, cervical scrapes of 306 women showing abnormal colposcopy were tested for cytology, HPV positivity, and the GynTect markers ASTN1, DLX1, ITGA4, RXFP3, SOX17, and ZNF671. Of all women, histopathological data were available. The overall sensitivity for GynTect to detect CIN3+ was 67.7% (95% CI 57.3%-77.1%) whereas sensitivity was significantly higher for women of age ≥ 30 years (p = 0.04). All cancer cases (n = 5) were detected by GynTect. The overall false positive rate (= 1-specificity) for women with no CIN was 17.4% (95% CI 12.5-23.1%), with a higher proportion among HPV-positive women (24.0%, 95% CI 16.0-33.6%). In a triage screening setting, where all women underwent HPV testing and the HPV positives in addition GynTect testing, the overall sensitivity would slightly decline but specificity would reach the maximum value of 88.7% (95% CI 83.7-92.6%). CONCLUSION: The GynTect® assay is a robust easy to use assay with high analytical sensitivity and specificity. Moreover, the performance of the assay based on cervical scrapes provides further evidence for the usefulness of methylation markers to detect HPV-positive women with clinically relevant disease.