Recently, in addition to some reports that miR-19a represses the expression of cell signaling pathway genes such as PTEN or TNF-α [18, 19, 23], the overexpression of miR-19a in gastric cancer has been demonstrated to promote the epithelial–mesenchymal transition by activating the PI3K/AKT pathway [26]. The gene discussed is PTEN; the disease is gastric cancer.