E2F1 and neuroblastoma: Additionally, Nutlin-3 has also been shown to sensitize p53 deficient chemoresistant neuroblastoma cells to chemotherapy induced apoptosis via upregulation of TAp73 and E2F1 (Ambrosini et al., 2007; Peirce and Findley, 2009b), and inhibition of P-glycoprotein (Michaelis et al., 2009).