Subsequent studies using mouse models with tissue-specific Dicer1 ablation reported that a single allele of Dicer1 in mice leads to oncogenesis in a lung cancer model caused by a K-ras protooncogene mutation [18], a retinoblastoma model caused by mutations in the tumor suppressor RB gene [19], and a lymphoma model caused by Eμ-myc [20]. This evidence concerns the gene RB1 and retinoblastoma.