Qin Y, Taylor W, Bamlet WR, et al. - Researchers assessed methylated DNA markers (MDM) in esophageal squamous cell carcinoma (ESCC) from three geographically and ethnically distinct groups. They also investigated the feasibility of assaying MDMs from DNA collected by swallowed balloon devices. They used ESCC and normal tissues collected from the populations of the United States, Iran, and China, to assay MDMs. For the same purpose, they used exfoliative cytology specimens collected by balloons in a Chinese population. They calculated areas under the receiver operating curve of MDMs differentiating ESCC from normal tissues. Findings revealed that, in tissues obtained from high- and low-incidence countries, an accurate discrimination of ESCC from normal esophagus was enabled by MDMs. According to preliminary data, levels of MDMs assayed in DNA from swallowed balloon devices increased with dysplasia grade.