In contrast with the effects of metaplasia- or cancer-derived fibroblasts on metaplastic cells, true normal-derived fibroblasts, isolated from histologically normal corpus mucosa without metaplasia or neoplasia obtained from the distal margins of esophagogastrectomies, did not promote polyp formation or expression of TROP2 or CEACAM5 compared with gastroid cells alone (Supplementary Figure 12B–D). The gene discussed is CEACAM5; the disease is cancer.