Chromatin complexes of RKO cells transfected with siRNA control and treated with ADR were immunoprecipitated with anti-p53, anti-ac-p53Lys373&382, and anti-PAN-acetylated Histone H4 (ac-H4) antibodies and PCR analysis was performed using specific primers flanking the p53 sequence-specific promoter regions. The gene discussed is TP53; the disease is polyarteritis nodosa.