Nucleolar stress is a well characterized consequence of the cancer chemotherapeutic Actinomycin D, which intercalates into rDNA and stalls rRNA synthesis by blocking RNA Polymerase I. Actinomycin treatment leads to rapid depletion of Nucleolin, phospho-Nucleolin (T76), and Nucleophosmin in murine VCM (Fig. 2A) and AC-16 cells (Additional file 1: Fig. S3A). Here, NPM1 is linked to cancer.