Determination of global DNA methylation level by methylation-sensitive comet assay in patients with urinary bladder cancer.

This article focuses on evaluating global DNA methylation levels in peripheral lymphocytes of patients with urinary bladder cancer using a methylation-sensitive comet assay, a technique that detects DNA methylation at the single-cell level via the McrBC enzyme. The study found significantly higher global DNA methylation in patients compared to matched healthy controls, with a cutoff value of 6.5% DNA methylation yielding 92% sensitivity but only 42% specificity for bladder cancer detection. The authors propose that this noninvasive assay could serve as a promising biomarker to reduce reliance on invasive diagnostic procedures like cystoscopy, although no correlation was observed between methylation levels and tumor grade or stage. Limitations include a relatively small sample size and low specificity, indicating the need for larger studies and comparison with established gene-specific methylation analyses.