This application describes methods and compositions for detecting and treating vimentin-associated neoplasia. Differential methylation of the vimentin nucleotide sequences has been observed in vimentin-associated neoplasia such as neoplasia of the upper or lower gastrointestinal tract, pancreas, and/or bladder. Nucleic acid sequences for regions of vimentin that are found to be differentially methylated are described. The present disclosure further describes bisulfite-converted vimentin template DNA sequences. Oligonucleotide primer sequences for use in assays (e.g., methylation-sensitive PCR assays or HpaII assays) designed to detect the methylation status of the vimentin gene are also described.