Additionally, loss of parietal cells results in deficiencies of a series of important mucosal growth factors, including transforming growth factor alpha (TGF-α), amphiregulin, heparin-binding epidermal growth factor (HB-EGF), and sonic hedgehog, thereby causing the transduction of chief cells into spasmolytic polypeptide-expressing metaplasia (SPEM) [9, 10], an important precancerous lesion of GC [11, 12]. The gene discussed is TGFA; the disease is gastric cancer.