Genetic differences between adenocarcinomas arising in Barrett's esophagusand gastric mucosa

Background & Aims: Barrett adenocarcinoma (BA+) and gastric adenocarcinoma comprise a related group of neoplasms that nevertheless have some distinct clinicopathologic characteristics. This study aimed at defining critical mo lecular abnormalities that may underlie differences between BA+ and gastric adenocarcinomas. Methods: We used comparative genomic hybridization for th e analyses of 34 xenografts of adenocarcinomas that arose from esophageal o r gastric origin. Results: All tumors, except one, exhibited DNA copy numbe r alterations. Losses in 4q and 14q and gains at 2p and 17q were more frequ ent in proximal (esophageal, gastroesophageal junction [GEJ], and cardia) t umors than in distal (body and antrum) tumors (P less than or equal to 0.05 0). These changes were significantly higher in BA+ compared with distal tum ors (P less than or equal to 0.040). In addition, losses in 5q and gains at 20q were significantly higher in BA+ than in distal cancers (P less than o r equal to 0.040). Losses in 5q and 8p and gains at 2q, 6p, 12p, and 20q we re significantly more frequent in BA+ tumors (P :5 0.050) than in GEJ and c ardiac tumors without associated Barrett's esophagus. Additionally, losses in 14q, which were common in proximal tumors, were more often seen in BA+ ( P = 0.100) than in other proximal tumors. Conclusion: Although these adenoc arcinomas share some common genetic alterations, the differences in the DNA copy numbers in BA+ cases suggest that unique genetic alterations may be i nvolved in these cancers' development.