Catecholamines upregulate metastasis‐associated in colon cancer 1 (MACC1), which binds directly to synaptophysin (SYP) via the β2-AR/c-Jun signaling pathway, thereby promoting the neuroendocrine phenotypic transformation of gastric cancer cells and accelerating metastasis (Fig. 2B) [32]. This evidence concerns the gene SYP and gastric cancer.