The common down-regulated genes found in GCA and GNCA are consistent with other studies on gastric cancer using microarrays, such as AKR1B10, ALDH3A1, ATP4B, CA2, IGFBP2, KLF4, MUC5AC, MUC6, TFF1, and TFF2[25], [29], [39]. The gene discussed is KLF4; the disease is gastric cancer.