• [ ] Estrogen stimulates cell proliferation in some tissues, via ERs

  Increased rate of cell division leads to more mistakes

  Mutant cells are stimulated to divide as well, increasing the chances that mutations accumulate

  Some tumors are ‘estrogen sensitive’: estrogen helps them to grow

• [ ] Antiestrogens

  Drugs can block the action of estrogen and thereby reduce the proliferation of mutant cells

  These drugs bind to ERs without turning on genes via EREs

  One of these drugs, tamoxifen, has been used in breast cancer treatment since the 1970s

Streptavidin immobilized on gold

Biotinylated DNA (ERE or random) captured

Estrogen receptor α (ERα) binding measured

Empty ERα Estrogen (E2)-ERα Tamoxifen (4OHT)-ERα