The objective of this research was to determine whether HDAC2 function is associated with gastric cancer progression. HDAC2 was knocked out in EPG85.257 cells using CRISPR/Cas9 and tumorigenesis pathways were evaluated. Cell proliferation, colony formation, wound healing and transwell invasion were inhibited in ΔHDAC2:EPG85.257 cells. Quantitative analyses revealed a significant downregulation of MMP1, p53, Bax, MAPK1, MAPK3, pro-Caspase3, ERK1/2, p-ERK1/2, AKT1/2/3, p-AKT1/2/3, p-NF-κB (p65), Twist, Snail and p-FAK transcripts/proteins, while SIRT1, PTEN, p21 and Caspase3 were upregulated in ΔHDAC2:EPG85.257 cells. These results indicated that HDAC2 enhanced migration, colony formation and transmigration ability. HDAC2 inhibition may improve gastric cancer chemotherapy pathways.