31st International Papillomavirus Conference & Clinical and Public Health Workshops February 28th – March 4th, 2017, Cape Town, South Africa.
Field:
Clinical Research – HPV Diagnostics and biomarkers Title
ASSOCIATION OF HPV METHYLATION WITH PRESENT AND FUTURE HIGH GRADE CERVICAL LESIONS IN THE NTCC COHORT.
Guglielmo Ronco 1, Valentina Fiano2, Chiara Grasso2, Morena Trevisan2, Raffaella Rizzolo1, Sara Tunesi1, Silvia Gori3, Alessandra Mongia4, Cristina Sani4, Francesca M. Carozzi4, Annarosa Del Mistro3, Laura De Marco2, Anna Gillio-Tos2, the NTCC working group.
1 Center for Cancer Epidemiology and Prevention (CPO), Turin, Italy 2. Unit of Cancer Epidemiology – CERMS, University of Turin, Italy 3. Cancer Research and Prevention Institute (ISPO), Florence, Italy 4. Istituto Oncologico Veneto (IOV), IRCCS, Padua, Italy
Objectives
Investigating the association of viral methylation at baseline with high-grade (hg) CIN present at recruitment and those detected later during follow-up.
Methods
Among women in the systematic NTCC biobank, those with a single hrHPV infection at recruitment, and subsequent colposcopy were considered. Methylation analyses were performed after DNA bisulfite modification by PCR targeting defined CpGs in the L1-I and L1-II regions, followed by pyrosequencing. For L1-I two consensus primer couples were generated, for HPV16,31,33,35,52,58 and for HPV39,45,51,59; dedicated primers were needed for HPV56 and 18. For L1-II, three consensus primers were generated, for HPV16, 33, 35, 52, 56, 58, HPV18, 51, and HPV39, 45, 59; HPV31 had dedicated primers. Women with CIN3+ detected (a) at recruitment and (b) during a 3-year follow-up (no hgCIN at baseline) were compared by ORs to those with no hgCIN in both periods (reference). Cut-of values were defined by ROC curve analysis.
Results
Data on 669 samples taken at recruitment for L1-I and 646 for L1-II are currently available. The proportion of positive (>10% of relevant CpGs methylated) samples in reference women was 50.4% and 41.2% respectively. Of women with CIN3+ present at recruitment 59.6% were positive for L1-I (OR 1.45; 95%CI 0.79-2.66) and 55.3% for L1-II (OR 1.77; 0.97-3.22). In women with CIN3+ detected during follow-up the proportion of positive samples was 80.0%, (OR=3.94; 1.30-11.94) for L1-I and 73.7% (OR=3.99; 1.42-11.25) for L1-II. Conclusions
The first longitudinal data on viral methylation show stronger association with future than with present CIN3+. Diferences between genotypes and efect of viral load are being investigated.
