title: Immunohistochemical evaluation of human epidermal growth factor receptor 2 and estrogen and progesterone receptors in invasive breast cancer in women.
abstract: BACKGROUND
  Estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER-2) expression are crucial in the biology of breast carcinoma. HER-2/neu gene is amplified and overexpressed in 15-30% of invasive breast cancers. HER-2-positive breast cancers have worse prognosis than HER-2 negative tumors and possess distinctive clinical features. The aim of this study was to assess the expression of HER2 in cancer tissue of patients with invasive breast cancer in correlation with tumor type, histological grade, tumor size, lymph node status, and expression of estrogen receptor and progesterone receptor.
  
  
  METHODS
  Formalin-fixed, paraffin-embedded tissues from 40 patients with invasive HER-2-positive breast cancer and from 191 patients with HER-2-negative breast cancer were used in this study. HER2 expression was determined using the test HerceptTest™ DAKO.
  
  
  RESULTS
  Among 231 cases of breast cancer, 18 invasive lobular carcinomas and 213 invasive ductal carcinomas were diagnosed. Sixty percent of HER-2-positive breast cancers were ER-positive compared with 77% in the HER-2-negative group (p = 0.002). The expression of PR was observed in 43% of HER-2-positive breast cancers and in 72% of HER2-negative tumors (p = 0.003). Excessive expression of HER2 protein was detected in 60% of patients positive for estrogen receptors, which may worsen prognosis in these patients.
  
  
  CONCLUSIONS
  Determination of HER2 overexpression in breast cancer patients, allows for a determination of a group of patients with a worse prognosis.
authors.affiliation: Department of Biophysics and Human Physiology, Medical University of Warsaw, Poland.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Badowska-Kozakiewicz
authors.forename: Maria
authors.initials: M
authors.lastname: Sobol
authors.forename: Janusz
authors.initials: J
authors.lastname: Patera
authors.forename: Wojciech
authors.initials: W
authors.lastname: Kozłowski
keywords: estrogen receptor; human epidermal growth factor receptor 2; invasive ductal carcinoma; invasive lobular carcinoma; progesterone receptor