RESUMO
BACKGROUND: DNA methylation is an essential factor in the progression of cervical intraepithelial neoplasia (CIN) to cervical cancer. The aim was to investigate the diagnostic value provided by methylation biomarkers of six tumor suppressor genes (ASTN1, DLX1, ITGA4, RXFP3, SOX17 and ZNF671) for cervical precancerous lesions and cervical cancer. METHODS: The histological cervical specimens of 396 cases including 93 CIN1, 99 CIN2, 93 CIN3 and 111 cervical cancers were tested for methylation-specific PCR assay (GynTect®) of score and positive rate. Among them, 66 CIN1, 93 CIN2, 87 CIN3 and 72 cervical cancers were further used for paired analysis. A chi-square test was used to analyze the difference of methylation score and positive rate in cervical specimens. The paired t-test and paired chi-square test were for analyzing the methylation score and positive rate in paired CIN and cervical cancer cases. The specificity, sensitivity, odds ratio (OR) and 95% confidence interval (95% CI) of the GynTect® assay for CIN2 or worse (CIN2 +) and CIN3 or worse (CIN3 +) were evaluated. RESULTS: According to the chi-square test trend, hypermethylation increased with severity of the lesions as defined by histological grading (P = 0.000). The methylation score above 1.1 was more common in CIN2 + than in CIN1. The DNA methylation scores in the paired groups of CIN1, CIN3 and cervical cancer were significant differences (P = 0.033, 0.000 and 0.000, respectively), except for CIN2 (P = 0.171). While the positive rate of GynTect® in each paired group had no difference (all P > 0.05). The positive rate of every methylation marker in the GynTect® assay showed differences in four cervical lesion groups (all P < 0.05). The specificity of GynTect® assay for detection of CIN2 + /CIN3 + were higher than high-risk human papillomavirus test. With CIN1 as a reference, the positive status of GynTect®/ZNF671 were significantly higher in CIN2 + : odds ratio (OR) 5.271/OR 13.909, and in CIN3 + : OR 11.022/OR 39.150, (all P < 0.001). CONCLUSION: The promoter methylation of six tumor suppressor genes is related to the severity of cervical lesions. The GynTect® assay based on cervical specimens provides diagnostic values for detecting CIN2 + and CIN3 + .
