To first investigate a possible requirement for REST in the NE to non-NE transition in vivo in SCLC, we crossed p53;fl/flRb;fl/flp130fl/fl mice to a conditional allele of Rest (Restfl)39 and analyzed tumors in triple and quadruple mutant mice upon Ad-CMV-Cre delivery to the lungs of these mice. Here, TP53 is linked to small cell lung carcinoma.