title: Relationships between hypoxia markers and the leptin system, estrogen receptors in human primary and metastatic breast cancer: effects of preoperative chemotherapy.
abstract: BACKGROUND
  Tumor hypoxia is marked by enhanced expression of hypoxia-inducible factor-alpha (HIF-1alpha) and glucose transporter-1 (Glut-1). Hypoxic conditions have also been associated with overexpression of angiogenic factors, such as leptin. The aim of our study was to analyze the relationships between hypoxia markers HIF-1alpha, Glut-1, leptin, leptin receptor (ObR) and other breast cancer biomarkers in primary and metastatic breast cancer in patients treated or untreated with preoperative chemotherapy.
  
  
  METHODS
  The expression of different biomarkers was examined by immunohistochemistry in 116 primary breast cancers and 65 lymph node metastases. Forty five of these samples were obtained form patients who received preoperative chemotherapy and 71 from untreated patients.
  
  
  RESULTS
  In primary tumors without preoperative chemotherapy, HIF-1alpha and Glut-1 were positively correlated (p = 0.02, r = 0.437). HIF-1alpha in primary and metastatic tumors without preoperative therapy positively correlated with leptin (p < 0.0001, r = 0.532; p = 0.013, r = 0.533, respectively) and ObR (p = 0.002, r = 0.319; p = 0.083, r = 0.387, respectively). Hypoxia markers HIF-1alpha and Glut-1 were negatively associated with estrogen receptor alpha (ERalpha) and positively correlated with estrogen receptor beta (ERbeta). In this group of tumors, a positive correlation between Glut-1 and proliferation marker Ki-67 (p = 0.017, r = 0.433) was noted. The associations between HIF-1alpha and Glut-1, HIF-1alpha and leptin, HIF-1alpha and ERalpha as well as Glut-1 and ERbeta were lost following preoperative chemotherapy.
  
  
  CONCLUSIONS
  Intratumoral hypoxia in breast cancer is marked by coordinated expression of such markers as HIF-1alpha, Glut-1, leptin and ObR. The relationships among these proteins can be altered by preoperative chemotherapy.
authors.affiliation: Department of Pathology, Medical University of Bialystok, Bialystok, Poland. kodamar@zeus.amb.edu.pl
authors.forename: Mariusz
authors.initials: M
authors.lastname: Koda
authors.forename: Luiza
authors.initials: L
authors.lastname: Kanczuga-Koda
authors.forename: Mariola
authors.initials: M
authors.lastname: Sulkowska
authors.forename: Eva
authors.initials: E
authors.lastname: Surmacz
authors.forename: Stanislaw
authors.initials: S
authors.lastname: Sulkowski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000737:chemistry* / Q000188:drug therapy* / Q000556:secondary; D015687:Cell Hypoxia; D017024:Chemotherapy, Adjuvant; D005260:Female; D051272:Glucose Transporter Type 1 / Q000032:analysis*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000032:analysis*; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D020738:Leptin / Q000032:analysis*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011960:Receptors, Estrogen / Q000032:analysis*; D054411:Receptors, Leptin / Q000032:analysis*; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D051272:Glucose Transporter Type 1; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D019394:Ki-67 Antigen; C515448:LEPR protein, human; D020738:Leptin; D011960:Receptors, Estrogen; D054411:Receptors, Leptin; C495677:SLC2A1 protein, human