RB1 and small cell lung carcinoma: Next, to elucidate the antitumor effects of AZD1775 against SCLC in vivo, we used cells derived from mice that were genetically engineered to spontaneously develop SCLC through conditional loss of Trp53, p130, and Rb1 (RPP) and Trp53, Rb1, and MYCT58A (RPM) (Schaffer et al., 2010; Mollaoglu et al., 2017).