Methylation in host and viral genes as marker of aggressiveness in cervical lesions: Analysis in 543 unscreened women

Objective: The present study aimed to evaluate the association between altered methylation and histologically confirmed high grade cervical intraepithelial neoplasia (hgCIN). Methods: Methylation levels in selected host (CADM1, MAL, DAPK1) and HPV (L1_I, L1_II, L2) genes were measured by pyrosequencing in DNA samples obtained from 543 women recruited in Curitiba (Brazil), 249 with hgCIN and 294 without cervical lesions. Association of methylation status with hgCIN was estimated by Odds Ratio (OR) with 95% confidence interval (CI). Results: The mean methylation level increased with severity of the lesion in the host and viral genes (p-trend < 0.05), with the exception of L1_II region (p-trend = 0.075). Positive association was found between methylation levels for host genes and CIN2 and CIN3 lesions respectively [CADM1: OR 4.17 (95%CI 2.03–8.56) and OR 9.54 (95%CI 4.80–18.97); MAL: OR 5.98 (95%CI 2.26–15.78) and OR 22.66 (95%CI 9.21–55.76); DAPK1: OR 3.37 (95%CI 0.93–12.13) and OR 6.74 (95%CI 1.92–23.64)]. Stronger risk estimates were found for viral genes [L1_I: OR 10.74 (95%CI 2.66–43.31) and OR 15.00 (95%CI 3.00–74.98); L1_II: OR 73.18 (95%CI 4.07–1315.94) and OR 32.50 (95%CI 3.86–273.65); L2: OR 4.73 (95%CI 1.55–14.44) and OR 10.62 (95%CI 2.60–43.39)]. The cumulative effect of the increasing number of host and viral methylated genes was associated with the risk of CIN2 and CIN3 lesions (p-trend < 0.001). Conclusions: Our results, empowered by a wide cervical sample series with a large number of hgCIN, supported the role of methylation as marker of aggressiveness.