title: [HER2 protein testing in gastric cancer: a retrospective analysis of 1 471 cases during two different periods in a single medical center].
abstract: OBJECTIVE
  To study the potential factors in influencing the performance of immunohistochemical testing for HER2 protein in gastric cancers.
  
  
  METHODS
  The HER2 protein expression status of 1 471 surgically resected archival gastric cancer cases in Drum Tower Hospital collected during two different periods was retrospectively analyzed. The materials included 957 cases tested during the period from 2007 to 2009 (group 1) and 514 cases from 2012 to 2013 (group 2). The test procedures and results observed during these two periods were compared.
  
  
  RESULTS
  The percentages of score 3 HER2 protein expression (14.4%, 74/514 versus 9.5%, 91/957) and score 2 or score 3 HER2 protein expression (27.2%, 140/514 versus 21.7%, 208/957) were both higher in group 2 than in group 1 (P < 0.05). In group 1, the cancer tissue was fixed in 10% formalin, stained manually with HER2 antibody A0485 (Dako) and assessed by different pathologists.In group 2, the tissue was fixed in 10% neutral buffered formalin (pH 7.2), stained using automated immunostaining system (Roche Benchmark XT) with HER2 antibody 4B5 (Ventana) and assessed by a specialized team of pathologists.
  
  
  CONCLUSIONS
  The results of HER2 immunostaining in gastric cancer are influenced by a number of factors including type of fixative, clone number of primary antibody, staining methods and experience of pathologists.
authors.affiliation: Department of Pathology, the Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China.
authors.forename: Xiangshan
authors.initials: X
authors.lastname: Fan
authors.affiliation: Department of Pathology, the Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Department of Pathology, the Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China.
authors.forename: Jieyu
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Pathology, the Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China.
authors.forename: Yifen
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Pathology, the Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Wu
authors.affiliation: Department of Pathology, the Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Pathology, the Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China.
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Pathology, the Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China. E-mail:fqmeng2004@126.com.
authors.forename: Fanqing
authors.initials: F
authors.lastname: Meng
mesh_terms: D000911:Antibodies, Monoclonal; D005404:Fixatives; D005557:Formaldehyde; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D012189:Retrospective Studies; D013194:Staining and Labeling; D013274:Stomach Neoplasms / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D005404:Fixatives; D005557:Formaldehyde; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human