TOP1 and cancer: CK2 substrates such as histone H4 (HIST1H4A), histone deacetylase 2 (HDAC2), members of the heterogeneous nuclear ribonucleoprotein family (HNRNPA1, HNRNPA2B1, HNRNPC), DNA topoisomerases 1 and 2 alpha (TOP1, TOP2A), eukaryotic translation initiation factor 2 subunit 2 (EIF2S2), Ras GTPase-activating protein-binding protein 1 (G3BP1), and others with critical roles in cancer cell physiology were also identified.