We used 581 mice divided into 14 experimental groups. In each experiment, mice were randomly divided into different subgroups (fig. S1 and table S1). INS-GAS mice with spontaneous gastric cancer were used as previously described (18 (link), 19 (link)). Denervation was achieved by subdiaphragmatic bilateral truncal vagotomy, unilateral vagotomy, or Botox local injection. The tumor prevalence/incidence, tumor size, tumor regeneration, pathological changes, gene expression profiles, and immunohisto-chemical biomarkers were examined after denervation. In vitro gastric organoid culture was performed as described previously (9 (link)). We also performed three cohort studies of human primary gastric cancer and gastric stump cancer, as well as gene expression profiling and KEGG pathway analysis. All studies and procedures involving animals and hu man subjects were approved by the Norwegian National Animal Research Authority, the Columbia University Institutional Animal Care and Use Committee, Gifu University, and the National Cancer Center Hospital East, Japan. Statistical comparisons were performed between experimental groups, between the anterior and posterior sides of the stomachs, and between groups of patients. See the Supplementary Materials for the complete Materials and Methods.