title: Human epidermal growth factor receptor 2 and estrogen receptor status in respect to tumor characteristics in non-metastatic breast cancer.
abstract: BACKGROUND
  The expressions of estrogen receptor (ER) and cell surface receptor, Tyrosine Kinase Human Epidermal Growth Factor Receptor 2 (HER 2), have emerged as the most important molecular biomarkers determining the breast cancer prognosis. In this study, interactions between ER and HER2 were assessed to determine if they modulate tumor characteristics.
  
  
  METHODS
  Tissue samples from 120 patients with early stage breast cancer receiving adjuvant chemotherapy were reviewed to evaluate ER and HER2 status quantified by immunohistochemistry and fluorescence in situ hybridization, and the correlation of ER and HER2 with patient characteristics and tumor pathology was studied.
  
  
  RESULTS
  A total of 37(30.8%) and 80(66.6%) out of 120 samples were HER2 (3+ by immunohistochemistry or positive by fluorescent in situ hybridization) and ER positive (by immunohistochemistry), respectively. ER-negative tumors were significantly more likely to be HER-2 positive than were ER-positive tumors (21.25%; odds ratio, 0.270; 95% CI, 0.119 to 0.612; P = 0.002). ER positivity was associated with <2 cm tumor size and higher histological grade (P = 0.007 and 0.019, respectively). No significant correlation was seen between the co-expression of HER2 and ER and tumor characteristics.
  
  
  CONCLUSIONS
  HER2 positive tumors were less common compared to ER positive tumors in early stage breast cancer Iranian patients. Also, higher histological grade among ER negative tumors showed higher aggressiveness of the tumor. Future studies are needed to evaluate the effect of receptor status on prognosis.
authors.affiliation: Chronic Respiratory Disease Research Center, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Hanifeh
authors.initials: H
authors.lastname: Mirtavoos-Mahyari
authors.affiliation: Chronic Respiratory Disease Research Center, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Adnan
authors.initials: A
authors.lastname: Khosravi
authors.affiliation: Mycobacteriology Research Center, NRITLD, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Esfahani-Monfared
keywords: Breast cancer; Estrogen receptor; Human Epidermal Growth Factor Receptor 2 (HER2); Tumor