In gastric cancer, PIWIL1 has been related to OCK2, ZNF503, PDE4D, ABL1, ABL2, LPAR1, SMAD2, WASF3, and DACH1 genes [73], and it has exhibited a regulation activity of epithelial-to-mesenchymal transition in endometrial cancer [74]. The gene discussed is PDE4D; the disease is gastric cancer.