Indeed, most of NPM1 interacting proteins contain multivalent arginine-rich motifs3 generally found in NoLS.20 Furthermore, the reduction of NPM1 levels is associated with the alteration of nucleolar structure.18 All these aspects substantiate the hypothesis that NPM1 behaves as a hub protein in nucleoli.2, 3 Relevant examples of NPM1 partners include ribosomal proteins (RPL5, RPS9, RPL23), viral proteins (Rev, Tat) and many tumor suppressors, including p14ARF, p53 and Fbw7γ.4, 16. This evidence concerns the gene NPM1 and neoplasm.