title: The controversial role of human chorionic gonadotropin in the development of breast cancer and other types of tumors.
abstract: BACKGROUND
  Breast cancer is the most often diagnosed tumor of women and one of the leading cause of cancer related death. Due to different known risk factors there are epidemiological differences. Beside genetic disorders and patient's age it is especially the age of the first full-term pregnancy and in this context the pregnancy hormone human chorionic gonadotropin that seems to play an important role.
  
  
  METHODS
  This review is based on a PubMed research in publications of the last 20 years. Only articles in English language were considered.
  
  
  RESULTS
  The effect of human chorionic gonadotropin on development of cancer is controversial. In fact, for breast cancer there is evidence that this hormone has a protective effect against tumorigenesis due the differentiation of the mammary tissue after a full term pregnancy through the downregulation of estrogen receptors.
  
  
  CONCLUSIONS
  Human chorionic gonadotropin has among promoting pregnancy important controversial functions especially in tumor development. The mechanisms that explain the pro- and anti-carcinogenic effects are not fully understood yet. It seems to have a protective effect on breast cancer through increasing differentiation and hereby decreasing susceptibility of the mammary tissue for toxicants. This knowledge might help developing a preventive agent in the next future that uses the anti-carcinogenic effect of human chorionic gonadotropin and thereby decrease the mortality out of breast cancer.
authors.affiliation: Department of Obstetrics and Gynecology, Ludwig-Maximilians-University Hospital, Maistrasse 11, 80337 Munich, Germany. Electronic address: Caroline.Gehring@med.uni-muenchen.de.
authors.forename: Caroline
authors.initials: C
authors.lastname: Gehring
authors.affiliation: Department of Neurology, Institute of Clinical Pharmacology, University Hospital Carl Gustav Carus, Freiberger Str. 37, 01067 Dresden, Germany. Electronic address: Timo.Siepmann@uniklinikum-dresden.de.
authors.forename: Timo
authors.initials: T
authors.lastname: Siepmann
authors.affiliation: Department of Obstetrics and Gynecology, Ludwig-Maximilians-University Hospital, Maistrasse 11, 80337 Munich, Germany. Electronic address: Helene.Heidegger@med.uni-muenchen.de.
authors.forename: Helene
authors.initials: H
authors.lastname: Heidegger
authors.affiliation: Department of Obstetrics and Gynecology, Ludwig-Maximilians-University Hospital, Maistrasse 11, 80337 Munich, Germany. Electronic address: Udo.Jeschke@med.uni-muenchen.de.
authors.forename: Udo
authors.initials: U
authors.lastname: Jeschke
mesh_terms: D016588:Anticarcinogenic Agents / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000209:etiology / Q000378:metabolism* / Q000517:prevention & control; D006063:Chorionic Gonadotropin / Q000502:physiology*; D005260:Female; D006801:Humans; D011247:Pregnancy
chemical_list: D016588:Anticarcinogenic Agents; D006063:Chorionic Gonadotropin
keywords: Breast cancer; Human chorionic gonadotropin (hCG); LH/hCG receptor; Pregnancy; TGFβ; hCG vaccines