p21 overexpression may lead to cell cycle arrest in G1 phase and induction of apoptosis (reviewed in [25]), a mechanism shown to occur in other brain tumor cell lines treated with different HDACis, such as Vorinostat, Trichostatin A [26], Entinostat [27], Dacinostat, or Sodium butyrate [28]. The gene discussed is CDKN1A; the disease is brain neoplasm.