Of such studies, all studies were eligible to calculate the hypermethylation rates of MGMT. A total of 2933 patients with SIL or CC from 25 studies (6 case-only studies[34, 43, 46, 48, 49, 51] and 19 case-control studies) were eligible to estimate the association of MGMT methylation status with the clinicopathological features. Here, MGMT is linked to squamous cell intraepithelial neoplasia.