TP53 and small cell lung carcinoma: To explore the effects of PRC2 inhibition on T cell responses to SCLC, we established primary lung tumor cell lines from a genetically engineered mouse model (GEMM) driven by biallelic loss of Trp53 and Rb1. Biallelic inactivation of TP53 and RB1 is a hallmark of human SCLC, and this GEMM closely mimics human SCLC (Sutherland et al., 2011, Meuwissen et al., 2003, George et al., 2015).