Indeed, while injection of synthetic miR-21 inhibitors (antagomiRs) was suggested to decrease tumor occurrence and growth in hepatocyte-specific PTEN knockout mice (LPTENKO) [36], both miR-21 antagomiRs or miR-21 genetic deletion did not affect HCC development in adult mice following injection of high doses of diethylnitrosamine (DEN) and CCl4 [37]. The gene discussed is PTEN; the disease is hepatocellular carcinoma.