title: Correlation of phosphorylated HER2 with clinicopathological characteristics and efficacy of trastuzumab treatment for breast cancer.
abstract: OBJECTIVE
  To determine the correlation of phosphorylated human epidermal growth factor receptor-2 (pHER2) with clinicopathological characteristics of breast cancer (BC) and patients' response to trastuzumab-based therapy.
  
  
  METHODS
  pHER2 was determinated immuno-histochemically in 88 cases of HER2-positive and 50 cases of HER2-negative BC. All patients with HER2-positive BC received trastuzumab-based therapy and 16 of them (18.2%) had disease progression during therapy treatment (i.e. trastuzumab-resistant).
  
  
  RESULTS
  pHER2 was predominantly expressed in HER2-positive BC, with 55 cases (62.5%) of tumours expressing pHER2. Six cases of HER2-negative cancer (12.5%) displayed positive expression of pHER2. Expression of pHER2 correlated with younger age of patients and negative oestrogen receptor status. Acquisition of resistance to trastuzumab correlated with negativity for pHER2 (p=0.028).
  
  
  CONCLUSIONS
  Positive expression of pHER2 may yield additional information regarding the poor prognosis of BC and could be used for pre-selection of patients with HER2-overexpressing BC displaying resistance to trastuzumab treatment.
authors.affiliation: Department of Pathology, University Hospital for Tumors, Sestre Milosrdnice Clinical Hospital Centre, Zagreb, Croatia.
authors.forename: Snježana
authors.initials: S
authors.lastname: Ramić
authors.forename: Ksenija
authors.initials: K
authors.lastname: Asić
authors.forename: Melita Perić
authors.initials: MP
authors.lastname: Balja
authors.forename: Frane
authors.initials: F
authors.lastname: Paić
authors.forename: Vesna
authors.initials: V
authors.lastname: Benković
authors.forename: Fabijan
authors.initials: F
authors.lastname: Knežević
mesh_terms: D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism*; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D008875:Middle Aged; D010766:Phosphorylation; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D000068878:Trastuzumab
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human
keywords: Breast cancer; HER2; phosphorylation; trastuzumab