The disclosure provides methods for identifying genomic loci (e.g., vimentin and/or SqBE18) that are differentially methylated in metaplasias (e.g., Barrett's esophagus) and/or neoplastic cancers (e.g., esophageal cancers). Identification of methylated genomic loci has numerous uses, including for example, to characterize disease risk, to predict responsiveness to therapy, to non-invasively diagnose subjects and to treat subjects determined to have gastrointestinal metaplasias and/or neoplasias.