After single guide RNA (sgRNA) selection and validation in NIH3T3 and GEMM-derived (Trp53/Rb1-deficient mice, RP) mouse embryonic fibroblasts (MEFs), we activated Myc, Mycn, or Mycl in genomically profiled (whole-exome sequencing (WES)) cells derived from early stage SCLC (RP) tumors14 (Supplementary Fig. 1b–d). Here, MYCL is linked to small cell lung carcinoma.