However, our data showing that not only Trp53-/-Rbpj-/- mutants, but also Trp53-/-Notch1-/-Notch2-/- and Trp53-/-Notch1-/- mutants develop tumors suggest that the tumor suppressor function of RBP-Jk in the brain is linked to the regulation of Notch signaling. This evidence concerns the gene NOTCH1 and neoplasm.