APAF1 and neoplasm: These include p53 upregulated modulator of apoptosis (PUMA), NADPH oxidase activator (NOXA),9,15,16 Bcl-2 family members Bax and Bid,17,18 and apoptotic peptidase activating factor 1 (Apaf-1).19 p53 also upregulates the expression of the death receptors Fas, DR4, and DR5.20–22 These few examples of p53-regulated genes belong to a growing list that emphasizes the multifactorial role of the p53 network in tumor suppression.