Study has found that KDM5D downregulation in gastric cancer cells inhibited cullin 4A (Cul4A) promoter demethylation, resulting in an increase in Zinc Finger E-Box Binding Homeobox 1 (ZEB1) and mesenchymal marker expression, a decrease in p21 and p53 expression, thereby promoting male gastric cancer epithelial-mesenchymal transition. The gene discussed is CDKN1A; the disease is gastric cancer.