title: Endometriosis and ovarian cancer: thoughts on shared pathophysiology.
abstract: BACKGROUND
  Endometriosis appears to predispose to ovarian cancer. How this may occur has been little discussed.
  
  
  METHODS
  This article reviews the English language literature for in vitro, animal, clinical, and epidemiologic studies linking the two conditions.
  
  
  RESULTS
  Pathology case series consistently report endometrioid and clear cell types of ovarian cancer arising from endometriotic foci. Epidemiologic studies have been consistent with this association. There are also marked similarities between the proposed etiology of ovarian cancer and the observed pathophysiology of endometriosis. Specifically, both are characterized by immune alterations. Both conditions are promoted by estrogen excess and by progesterone deficit. Finally, steroid hormones interacting with the immune system may stimulate both endometriosis and ovarian cancer. I propose that the biology common to endometriosis and ovarian cancer represents not just a parallelism, but instead a causal pathway: aberrant immune function, fed by and feeding on estrogens, unbalanced by progesterone, may create a positive feed-forward loop that enhances the growth and invasiveness of endometriosis and promotes its malignant transformation.
  
  
  CONCLUSIONS
  The same pathophysiology may orchestrate the progression of endometriosis and its transformation to endometroid and clear cell ovarian neoplasias. This notion of a unifying biology suggests a directed approach to future research and identifies possible chemoprevention strategies for women with endometriosis.
authors.affiliation: Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, the University of Pittsburgh Cancer Institute, Pittsburgh, PA 15261, USA. repro@vms.cis.pitt.edu
authors.forename: Roberta B
authors.initials: RB
authors.lastname: Ness
mesh_terms: D000728:Androgens / Q000502:physiology; D002471:Cell Transformation, Neoplastic; D004715:Endometriosis / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D004967:Estrogens / Q000502:physiology; D005260:Female; D006801:Humans; D007249:Inflammation; D010051:Ovarian Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology; D011374:Progesterone / Q000502:physiology
chemical_list: D000728:Androgens; D004967:Estrogens; D011374:Progesterone