Induction of tamoxifen resistance in breast cancer cells by ELF electromagnetic fields

Biochem Biophys Res Commun. 2005 Nov 4;336(4):1144-9. doi: 10.1016/j.bbrc.2005.08.243.


The incidence of breast cancer in western societies has been rising ever since the Second World War. Besides the exposure to a multitude of new chemical compounds, electromagnetic field exposure has been linked to breast cancer through a radiation-mediated anti-melatonin pathway. We investigated, whether low-frequency electromagnetic field exposure interferes with the anti-estrogenic activity of tamoxifen. Two different clones of the breast cancer cell line MCF-7 were exposed to highly homogeneous 50Hz electromagnetic fields and IC(50) values were calculated from dose-response curves of tamoxifen at various field intensities. An intensity-dependent shift of tamoxifen dose-response curves to higher concentrations with a maximal response at 1.2muT was observed. Hypothetically, electromagnetic field exposure could contribute to tamoxifen resistance observed in breast cancer after long-term treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breast Neoplasms
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Proliferation / radiation effects
  • Drug Resistance, Neoplasm / radiation effects*
  • Electromagnetic Fields / adverse effects*
  • Estrogen Antagonists / pharmacology*
  • Female
  • Humans
  • Tamoxifen / pharmacology*


  • Estrogen Antagonists
  • Tamoxifen