title: Discordant human epidermal growth factor receptor 2 and hormone receptor status in primary and metastatic breast cancer and response to trastuzumab.
abstract: BACKGROUND
  Recent studies have shown that the human epidermal growth factor receptor 2 status of a metastatic site may differ from that of the primary site. This difference may influence patient prognosis and response to therapy.
  
  
  METHODS
  We conducted a retrospective study using immunohistochemistry and/or fluorescent in situ hybridization to compare human epidermal growth factor receptor 2 and hormone receptor status in primary and metastatic breast cancers.
  
  
  RESULTS
  Fifty-six patients were included in this study. Conversion from hormone receptor positive in the primary tumor to hormone receptor negative in the metastasis occurred in 12 patients (21.4%), and hormone receptor negative to hormone receptor positive conversion occurred in two patients (3.6%). Human epidermal growth factor receptor 2 status was discordant between primary and metastatic lesions in seven patients (12.5%). All of the five patients who converted from human epidermal growth factor receptor 2 negative status to human epidermal growth factor receptor positive received trastuzumab-based chemotherapy. Overall response rate and median progression-free survival for concordant human epidermal growth factor receptor 2 positive patients were 69.2% and 16.9 months, whereas that of patients with positive conversion of human epidermal growth factor receptor 2 were 40.0% and 7.6 months, respectively (overall response rate; P = 0.169 and progression-free survival; P = 0.004).
  
  
  CONCLUSIONS
  Discordance in human epidermal growth factor receptor 2 and hormone receptor status between primary and metastatic tumors was observed, which led to altered treatment decisions. Evaluation of human epidermal growth factor receptor 2 and hormone receptor in metastatic tumors should be considered in patients with breast cancer.
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, 28 Yongon-Dong, Chongno-Gu, Seoul 110-744, South Korea.
authors.forename: Hye Jung
authors.initials: HJ
authors.lastname: Chang
authors.forename: Sae-Won
authors.initials: SW
authors.lastname: Han
authors.forename: Do-Youn
authors.initials: DY
authors.lastname: Oh
authors.forename: Seock-Ah
authors.initials: SA
authors.lastname: Im
authors.forename: Yoon Kyung
authors.initials: YK
authors.lastname: Jeon
authors.forename: In Ae
authors.initials: IA
authors.lastname: Park
authors.forename: Wonshick
authors.initials: W
authors.lastname: Han
authors.forename: Dong-Young
authors.initials: DY
authors.lastname: Noh
authors.forename: Yung-Jue
authors.initials: YJ
authors.lastname: Bang
authors.forename: Tae-You
authors.initials: TY
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001859:Bone Neoplasms / Q000737:chemistry / Q000556:secondary; D001943:Breast Neoplasms / Q000737:chemistry* / Q000188:drug therapy / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008113:Liver Neoplasms / Q000737:chemistry / Q000556:secondary; D008175:Lung Neoplasms / Q000737:chemistry / Q000556:secondary; D008198:Lymph Nodes / Q000737:chemistry / Q000473:pathology; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009367:Neoplasm Staging; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*; D012189:Retrospective Studies; D000068878:Trastuzumab; D016896:Treatment Outcome
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D000068878:Trastuzumab; C508053:ERBB2 protein, human