This study will involve collection of tissue via endoscopic biopsy in 10 patients with normal endoscopic appearance from the esophagus, stomach and duodenum. Ambion miR oligonucleotide arrays will be utilized to profile miRs that are specifically expressed in epithelial biopsies from the duodenum, stomach, and esophagus. Total RNA will be extracted from independent biopsy samples using the mirVana(R) micro RNA isolation kit from Ambion. The Ambion Flash PAGE(R) electrophoresis system will be used to resolve mature miRs from the larger pre-miR species. Mature miRs will be labeled and hybridized to Ambion mirVana miR(R)arrays, which will be scanned to identify miRs that are regulated under these circumstances. Signals from the microarrays will be processed using the R functions of Bioconductor for normalization and background correction and RMA for summarization. Statistical significance will be determined using Insightful S+ functions and assuming a least pooled error model. Potential targets will be confirmed by northern blotting. The routine histology sample will be reviewed simply to exclude other, unexpected microscopic pathology. Benign histologic findings such as minor inflammation, will not exclude the patient from inclusion. If there is a wide variation in miR expression, then the histology might be needed to help explain such variation.