ESR1 and gastric cancer: Oestrogen inhibits miR‐145 expression in splenic lymphocytes and epithelial endometrial cells, while miR‐145 targets Esr1 in human breast cancer cells.29, 30, 31 Similarly, EGFR down‐regulates the expression of miR‐145 in lung cancer cells, while miR‐145 and miR‐455 down‐regulate EGFR expression in human lung adenocarcinoma and gastric cancer cells, respectively.32, 33, 34