Overall, this study demonstrates that HDAC3 may be a positive regulator of EMT and tumor metastasis in gastric cancer through transcriptional repression of E-cadherin via C/EBPβ and NFκB-p65 gene regulation, which can be significantly inhibited by treatment with Honokiol or HDAC3 inhibitors. The gene discussed is CEBPB; the disease is gastric cancer.