Here, we report on the anti-EMT effect of ATO in gastric cancer cells by demonstrating dephosphorylation of JAK2/STAT3 and modulation of EMT markers including Snail1 and E-cadherin by ATO, and suggest that SHP-1 might be an important mediator for inactivation of the JAK2/STAT3 signaling pathway. The gene discussed is CDH1; the disease is gastric cancer.