Summary: In the current protocol, we propose a study to evaluate a novel, combined esophageal sponge-methylation biomarker strategy for the early detection of esophageal squamous cell carcinoma (ESCC) as well as its precursor, esophageal squamous dysplasia (ESD). This strategy leverages the 'EsophaCap', a swallowable, retrievable sponge, with subsequent evaluation of the sample using a novel molecular biom...