Gene expression profiling of esophageal adenocarcinoma

Specimens were collected from esophageal adenocarcinoma patients undergoing esophagectomy for adenocarcinoma at the University of Michigan Health System between 1991 and 2004. Written consent was obtained from each patient according to the approval and guidelines of the University of Michigan institutional review board. Patients receiving treatment with chemotherapy and/or radiotherapy prior to surgery were excluded. Tissue samples were fresh-frozen in liquid nitrogen and stored at −80 °C until use. Cellularity of tumor samples were assured to be greater than 70% before sample RNA was isolated. RNA from 22 adenocarcinoma samples was extracted and processed for hybridization on Affymetrix Human Genome U133A 2.0 Array.