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

Abstract

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+.