AbstractWe previously showed that silencing of TSLC1, recently renamed CADM1, is functionally involved in high‐risk HPV‐mediated cervical carcinogenesis. CADM1 silencing often results from promoter methylation. Here, we determined the extent of CADM1 promoter methylation in cervical (pre)malignant lesions and its relation to anchorage‐independent growth and gene silencing to select a CADM1‐based methylation marker for identification of women at risk of cervical cancer. Methylation‐specific PCRs targeting three regions within the CADM1 promoter were performed on high‐risk HPV‐containing cell lines, PBMCs, normal cervical smears, and (pre)malignant lesions. CADM1 protein expression in cervical tissues was analysed by immunohistochemistry. All statistical tests were two‐sided. Density of methylation was associated with the degree of anchorage‐independent growth and CADM1 gene silencing in vitro. In cervical squamous lesions, methylation frequency and density increased with severity of disease. Dense methylation (defined as ≥ 2 methylated regions) increased from 5% in normal cervical samples to 30% in CIN3 lesions and 83% in squamous cell carcinomas (SCCs) and was significantly associated with decreased CADM1 protein expression (p < 0.00005). The frequency of dense methylation was significantly higher in ≥ CIN3 compared with ≤ CIN1 (p = 0.005), as well as in SCCs compared with adenocarcinomas (83% versus 23%; p = 0.002). Detection of dense CADM1 promoter methylation will contribute to the assembly of a valuable marker panel for the triage of high‐risk HPV‐positive women at risk of ≥ CIN3. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.