Abstract B01: PEG3 DNA methylation and cervical intraepithelial neoplasia in African American and European American women

Background: Epigenetic mechanisms are hypothesized to be etiologically involved in progression of cervical intraepithelial neoplasia (CIN) to invasive cervical cancer (ICC), although empirical data are lacking. Methods: A total of 304 women were enrolled at the time of colposcopic evaluation following an abnormal liquid-based cytology screen. HPV was genotyped by HPV linear array. To ascertain the presence of CIN, the biopsies underwent pathologic review. DNA methylation was measured at differentially methylated regions (DMRs) regulating genomic imprinting of IGF2/H19 PEG1/MEST, KCNQ1OT1, MEG3, HYMAI, PEG10 and PEG3 imprinted domains, using Sequenom EpiTYPER assays. Logistic regression models were used to estimate odd ratios (ORs) and to evaluate the associations between HPV infection and DMR methylation, respectively. Results: After accounting for age, HPV infection, parity, hormonal contraceptive use, and cigarette smoking, methylation differences at the PEG3 DMR were associated with a modest but significant higher risk of CIN2/3 (OR=1.08, 95%CI 1.02-1.18, p=0.022) in all women. This association remained significant in European American (OR=1.13, 95%CI 1.03-1.27, p=0.011), but not in African American women (OR=1.03, 95%CI 0.90-1.16, p=0.715). HPV infection was associated with altered PEG3 DMR methylation in both groups of women, an association that was also stronger in European Americans (β= -3.42, p=0.041), than in African Americans (β= -2.55, p=0.132). Though altered methylation at IGF2/H19 and PEG10 DMRs was associated with CIN1, no associations were observed with CIN2/3 lesions. No associations were found for PEG1/MEST, KCNQ1OT1 , MEG3 , and HYMAI DMRs. Conclusions: Aberrant DNA methylation at the regulatory region of the PEG3 imprinted gene may increase susceptibility to CIN2/3; an association that may be stronger in European American women and which persisted after accounting for HPV infection. If confirmed in larger studies, these findings support the hypothesis that DNA methylation at PEG3 may represent a susceptibility locus that can be exploited to identify, from among a large number of abnormal colposcopy cases, those likely to progress to CIN or worse. Citation Format: Adriana C. Vidal, David Skaar, Zhiquing Huang, Fidel Valea, Rex Bentley, Margaret Gradison, Kimberly S. H. Yarnall, Anne Ford, Francine Overcash, Katherine Grant, Susan K. Murphy, Cathrine Hoyo. PEG3 DNA methylation and cervical intraepithelial neoplasia in African American and European American women. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr B01.