title: Evaluation of serum HER2-ECD levels in patients with gastric cancer.
abstract: BACKGROUND
  Determination of the human epidermal growth factor receptor 2 (HER2) status of gastric cancer patients is indispensable in clinical practice. However, the clinical value of serum HER2-extracellular domain (ECD) in gastric cancer has not yet been defined.
  
  
  METHODS
  The serum level of HER2-ECD was measured using the chemiluminescence immunoassay method, and its relationship with tissue HER2 status and clinicopathologic features was examined. Transition of serum HER2-ECD level was examined in patients during chemotherapy to clarify the correlation between changes in the level of HER2-ECD in serum and response to chemotherapy.
  
  
  RESULTS
  A total of 150 gastric cancer patients were enrolled in this study; changes in HER2-ECD level were examined in 36 of these patients during chemotherapy. Serum levels of HER2-ECD ranged from 4.8 to 180.0 ng/ml (median 9.2 ng/ml) and were positive (cutoff value 15.2 ng/ml) in ten patients (6.7 %). There was a significant correlation between serum HER2-ECD level and tissue HER2 status (P < 0.001); however, no correlation with TNM stage was found. Change in serum HER2-ECD level during chemotherapy was significantly correlated with response to chemotherapy in patients with HER2-positive tumor tissue.
  
  
  CONCLUSIONS
  Serum HER2-ECD is a potential biomarker of gastric cancer and could be used as a diagnostic marker with regard to tissue HER2 status, and also as a monitoring marker in relation to response to chemotherapy.
authors.affiliation: Department of Gastroenterologic Surgery, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan, oya-ma@staff.kanazawa-u.ac.jp.
authors.forename: Katsunobu
authors.initials: K
authors.lastname: Oyama
authors.forename: Sachio
authors.initials: S
authors.lastname: Fushida
authors.forename: Tomoya
authors.initials: T
authors.lastname: Tsukada
authors.forename: Jun
authors.initials: J
authors.lastname: Kinoshita
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Shoji
authors.forename: Shinichi
authors.initials: S
authors.lastname: Nakanuma
authors.forename: Koichi
authors.initials: K
authors.lastname: Okamoto
authors.forename: Seisho
authors.initials: S
authors.lastname: Sakai
authors.forename: Isamu
authors.initials: I
authors.lastname: Makino
authors.forename: Keishi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Hironori
authors.initials: H
authors.lastname: Hayashi
authors.forename: Masafumi
authors.initials: M
authors.lastname: Inokuchi
authors.forename: Hisatoshi
authors.initials: H
authors.lastname: Nakagawara
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Miyashita
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Tajima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takamura
authors.forename: Itasu
authors.initials: I
authors.lastname: Ninomiya
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Kitagawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujimura
authors.forename: Ryousuke
authors.initials: R
authors.lastname: Tajiri
authors.forename: Akishi
authors.initials: A
authors.lastname: Ooi
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ohta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood*; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000097:blood; D009367:Neoplasm Staging; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000097:blood*; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human