Aberrant DNA methylation has been shown to play important roles during multistage carcinogenesis in various human organs. The aim of this study was to evaluate the significance of DNA methyltransferase 1 (DNMT1) protein expression during cervical carcinogenesis. We carried out an immunohistochemical examination for DNMT1 in 34 samples of histologically normal squamous epithelium, 36 samples of low-grade cervical intraepithelial neoplasia (CIN), 61 samples of higher-grade CIN and 30 samples of squamous cell carcinoma of the uterine cervix. The DNMT1 protein expression score, reflecting the intensity and incidence of DNMT1 nuclear immunoreactivity, was increased even in low-grade CIN (P
