Fig. 1.

Patient samples. Progressor and non-progressor sampling over time and space. Three endoscopic biopsies were collected from all patients at the first time point. Three additional biopsies were collected from the four non-progressors during a follow-up endoscopy 73–91 months after the first time point. The distance to the GEJ was recorded for all endoscopic biopsies. Eight biopsies were collected from the surgical resection specimens of the four progressors, 3–74 months after the first time point. The location of the surgical biopsies relative to the GEJ and to each other were recorded. Each biopsy, whether endoscopic or surgical, was then split into four sections defined as baguette sections (along the long axis of the grain-of-rice-shaped biopsies), and two adjacent crypts (shown here enlarged and out of scale) were pulled from each section. The DNA of the eight individual crypts and of the remaining epithelium was extracted, yielding nine samples per biopsy