RB1 and small cell lung carcinoma: Moreover, ZFP36L1 protein was largely absent in the majority of cells in mouse SCLC lung tumors derived from a CRISPR-based SCLC genetically engineered mouse model (Fig. 3e, f) where autochthonous lung tumors are generated by CRISPR/Cas9 editing of Rb1, Trp53, and Rbl2 in somatic cells in the lung15,31.