MYC and breast neoplasm: G4 stabilization in oncogene promoters by small molecules leads to down‐regulation of the expression of their respective genes.[10, 11, 12, 13] Up to 80 % of all solid tumours (including gastrointestinal, ovarian and breast tumours) overexpress c‐Myc.[14] It has been proposed that the G4 present in NHE III1 in the c‐Myc gene is crucial for transcriptional silencing.[15, 16] This element is comprised of 27 nucleotides containing five G‐tracts of which G‐tracts 2, 3, 4 and 5 form a parallel G4 as the major conformation.