Clinical Utility of Cytological Methylation Assay in Cervical Cancer Screening Across Various Cervical Transformation Zones

Type I to III cervical transformation zones (TZ-1 to TZ-3) may have various effects on cervical cancer screening and diagnostic outcomes. This study aims to evaluate the clinical utility of the cytological PAX1/JAM3 methylation (CISCER) assay in cervical cancer screening, especially in TZ-3 women. Between November 2020 and October 2022, 1782 women referred for colposcopy underwent liquid-based cytology (LBC), high-risk human papillomavirus (hrHPV) genotyping, and CISCER testing. After applying inclusion criteria, 1398 women were analyzed, including 1190 with documented TZ classification. Diagnostic performance for detecting cervical intraepithelial neoplasia grade 3 or worse (CIN3+) was compared across TZ subgroups. For CIN3+ detection, CISCER showed sensitivities of 67.4%, 72.0%, 48.3%, and 81.5% and specificities of 91.0%, 94.2%, 91.3%, and 89.8% in all women, TZ-1, TZ-2, and TZ-3, respectively. Compared with LBC ≥ ASC-US, hrHPV positivity, or HPV16/18 positivity, CISCER achieved the highest diagnostic accuracy, with AUC values of 0.792, 0.831, 0.698, and 0.856 across the respective groups. In both the overall cohort and TZ-3 subgroup, CISCER positivity was associated with the highest CIN3+ risk (34.6% and 31.4%) and required the fewest colposcopy referrals per CIN3+ detected (2.9 and 3.2). Combining hrHPV testing with CISCER further improved risk stratification. CISCER demonstrated superior diagnostic performance across TZ types, particularly in TZ-3, enabling improved CIN3+ risk discrimination while substantially reducing unnecessary colposcopy referrals compared with conventional cytology and HPV genotyping.