title: [Delay in formalin fixation and HER2 testing in gastric cancer].
abstract: OBJECTIVE
  To evaluated HER2 status using immunohistochemistry (IHC) assay and fluorescence in situ hybridization (FISH) at two different time points of tissue fixation after surgical resection of gastric cancer, emphasizing the importance of standard operation and quality control in HER2 testing.
  
  
  METHODS
  Forty-one resection specimens of advanced gastric cancer were collected with tissue fixation periods of < 30 min or > 30 min after surgical resection. HER2 status was evaluated by immunohistochemistry (IHC) assay and fluorescence in situ hybridization (FISH).
  
  
  RESULTS
  The frequency of HER2 expression by IHC in the samples with fixation time of < 30 min was higher than that in those of > 30 min (P < 0.05). However, no significant difference was observed by FISH (P > 0.05) between the two groups. Samples of < 30 min fixation time had high concordant results between IHC and FISH (100.0% for both positive and negative cases, Rho = 0.724, P < 0.05). In addition, HER2 expression by IHC was significantly correlated with Lauren classification, histologic differentiation, TNM stage and gender (P < 0.05).
  
  
  CONCLUSIONS
  The time to tissue fixation after surgical resection of more than 30 min has deleterious effect on the detection of HER2 by IHC although FISH testing is not affected.
authors.affiliation: Department of Pathology, Affiliated Tumor Hospital of Guangxi Medical University, Nanning 530021, China.
authors.forename: Lixia
authors.initials: L
authors.lastname: Zeng
authors.forename: Junqi
authors.initials: J
authors.lastname: Huang
authors.forename: Yun
authors.initials: Y
authors.lastname: Ma
authors.forename: Yixiao
authors.initials: Y
authors.lastname: Liu
authors.forename: Yuying
authors.initials: Y
authors.lastname: Wei
authors.forename: Qian
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: E-mail: dr.hongtaoye@googlemail.com.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Ye
mesh_terms: D000368:Aged; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D013274:Stomach Neoplasms / Q000737:chemistry* / Q000473:pathology / Q000601:surgery; D013997:Time Factors; D016707:Tissue Fixation / Q000379:methods*
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases