HMGN1 and breast cancer: Single targeting of the G4 located in the HMGN1 promoter—unique to MCF7 cells and not detected in other cancer cell lines76—led to the greatest transcriptional suppression measured in MCF7 (a 99% reduction), confirming a strong link between transcriptional activity and ligand sensitivity that indicates a substantial contribution of the HMGN1-G4 in sustaining elevated expression levels of HMGN1 in breast cancer cells.