title: Role of melatonin on electromagnetic radiation-induced oxidative stress and Ca2+ signaling molecular pathways in breast cancer.
abstract: OBJECTIVE
  Exposure to electromagnetic radiation (EMR) may increase breast cancer risk by inducing oxidative stress and suppressing the production of melatonin. Aim of the present review is to discuss the mechanisms and risk factors of EMR and oxidative stress-induced breast cancer, to summarize the controlled studies evaluating measures for prevention, and to conclude with evidence-based strategies for prevention.
  
  
  METHODS
  Review of the relevant literature and results from our recent basic studies, as well as critical analyses of published systematic reviews were obtained from the Pubmed and the Science Citation Index.
  
  
  RESULTS
  It has been proposed that chronic exposure to EMR may increase the risk of breast cancer by suppressing the production of melatonin; this suppression may affect the development of breast cancer either by increasing levels of circulation of estrogen or through over production of free oxygen radicals. Most epidemiological studies have also indicated overall effect of EMR exposure in premenopausal women, particularly for estrogen receptor positive breast tumors. Enhanced voltage-dependent Ca(2+) current and impaired inhibitory G-protein function, and derangement of intracellular organelles with a Ca(2+) buffering effect, such as endoplasmic reticulum and mitochondria have been also shown to contribute to disturbed Ca(2+) signaling in breast cancer.
  
  
  CONCLUSIONS
  Melatonin may modulate breast cancer through modulation of enhanced oxidative stress and Ca(2+) influx in cell lines. However, there is not enough evidence on increased risk of breast cancer related to EMR exposure.
authors.affiliation: Department of Biophysics, Medical Faculty, Süleyman Demirel University, Isparta, Turkey. mustafanaziroglu@sdu.edu.tr
authors.forename: Mustafa
authors.initials: M
authors.lastname: Naziroğlu
authors.forename: Sümeyye
authors.initials: S
authors.lastname: Tokat
authors.forename: Seda
authors.initials: S
authors.lastname: Demirci
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D002118:Calcium / Q000378:metabolism / Q000528:radiation effects; D060733:Electromagnetic Radiation; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008550:Melatonin / Q000096:biosynthesis / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism / Q000528:radiation effects; D018384:Oxidative Stress / Q000528:radiation effects*; D015398:Signal Transduction / Q000528:radiation effects
chemical_list: D008550:Melatonin; D002118:Calcium