Abstract 5011: Genome-wide methylation profiling identifies hypermethylated biomarkers in high-grade cervical intraepithelial neoplasia

Abstract

Abstract Introduction: Cervical cancer is the second most common cancer in women worldwide and development of cervical cancer goes through different well-defined premalignant stages. Epigenetic modifications, such as aberrant DNA promoter methylation is frequently observed in cervical cancer. Identification of hypermethylated regions that allow discrimination between normal cervical epithelium and high-grade cervical intraepithelial neoplasia or worse (CIN2+) by DNA methylation state may improve current population-based screening programs for cervical cancer. In this study, the DNA methylome of CIN3 lesions were characterized using genome-wide methylation screening to identify potential biomarkers for early diagnosis of cervical neoplasia. Methods and results: Methyl-DNA ImmunoPrecipitation (MeDIP) assay combined with DNA microarray hybridization was used to compare DNA methylation patterns of epithelial cells derived from CIN3 lesions with normal cervical epithelium. In total, 80 hypermethylated differentially methylated regions (DMRs) were identified that significantly distinguished CIN3 lesions from normal cervice. Selected DMRs (n=9) were evaluated by methylation-specific PCR (MSP) on additional tissue specimens including normal cervix, CIN2/3 and cervical cancer samples and showed hypermethylation in up to 94.7% in CIN2/3 and 100% in cervical cancers. Quantitative MSP (QMSP) for two candidate biomarkers was applied to explore the test performance in a large series of cervical scrapings. Frequency and relative level of DNA methylation were significantly different between normal and cancer samples (p<0.05). In cervical scrapings from patients referred with an abnormal Pap smear, frequency and relative level of DNA methylation were also related with increasing severity of the underlying CIN lesion (p<0.01) In addition, ROC analysis showed that the methylation level was discriminative between low-grade CIN lesions and CIN2+ (p<0.05). Conclusion: Our study demonstrates specific DNA methylation patterns in high-grade CIN lesions through the newly identified discriminative hypermethylated DMRs and represents candidate biomarkers for early detection of high-grade CIN. This study was supported by the Dutch Cancer Society (NKB) (project-number RUG 2004-3161) and by OncoMethylome Sciences S.A., Liège, Belgium. CG was funded by the German Ministry of Education and Research (BMBF) within the NGFN-PLUS project PKT-01GS08111. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5011. doi:1538-7445.AM2012-5011