Of significant interest to breast cancer are regulatory G4 and i-motif elements within the promoter regions of key oncogenes including BCL-2 (56,75–79), c-MYC (77,80–84), KRAS (85–88), hTERT (89–92), PDGFR-β (93,94), c-KIT (95–102), RET (103,104) and VEGF (105). This evidence concerns the gene BCL2 and breast cancer.