The key insight that sparked Darwin's theory of descent with modification was that he compared and contrasted differences between living and extinct species across time and space. He likely arrived on this theory in large part through his culinary experiences, set against the background of the rugged Patagonian landscape of Southern Argentina. We feel that further integration of research into gastric and esophageal adenocarcinoma may benefit both fields and similarly lead to a coherent understanding of cancer progression in the upper gastrointestinal tract across time and space. Although the environmental trigger differs between carcinogenesis of the stomach and distal esophagus, there remain many important lessons to be learned from comparing precursor stages, such as intestinal metaplasia, across anatomic borders. This analysis will absolutely require detailed sampling within and between these related species, but most importantly we need higher resolution clinical phenotyping to relate genomic differences to drivers of morphologic evolution. In the end, this may provide us with a new phylogeny showing key differences between esophageal and gastric adenocarcinoma.