To further explore the relationship between PCDHGA9 and EMT, we evaluated PCDHGA9 expression and the molecular hallmarks of EMT and found a positive correlation between PCDHGA9 and E-cadherin expression but a negative correlation between PCDHGA9 and N-cadherin, Vimentin and Twist expression in clinical GC tissues, which provided convincing evidence that PCDHGA9 inhibits EMT in GC metastasis. The gene discussed is TWIST1; the disease is gastric cancer.