The cyclin-dependent kinase inhibitor CDKN1A (encoding p21WAF1/CIP1) is upregulated by vorinostat and other HDACIs in several cancer cell lines, an effect that correlates with cell cycle arrest and has been suggested to induce protection from cell death mediated by HDACIs (Burgess et al, 2001, 2004). The gene discussed is CDKN1A; the disease is cancer.