TOP1 and cancer: To determine whether the significant impact on the G4-associated genome instability is characteristic of Top1 mutants with changes in the C-terminal domain like human W736Stop and yeast Y740*, we surveyed the cancer mutation database obtained from the Catalogue of Somatic Mutations In Cancer (COSMIC) at https://cancer.sanger.ac.uk/cosmic through file CosmicMutantExport_v94.tsv (accessed on 12 September 2025).