title: Comparison of dual-color in-situ hybridization and fluorescence in-situ hybridization in HER2 gene amplification in breast cancer.
abstract: BACKGROUND
  HER2 is a prognostic factor in breast cancer, and is predictive of the effects of HER2-targeted drugs. HER2 tests are essential in invasive and metastatic breast cancer. Dual-color in-situ hybridization (DISH) is a novel genetic test, and we investigated its utility in HER2 testing in breast cancer.
  
  
  METHODS
  Using DISH and two FISH methods (FISH method 1, FISH method 2) with representative slices of surgical specimens from 134 invasive breast cancer patients, we performed HER2 gene testing and compared the results for HER2 gene/CEP17 signal ratio and HER2 gene diagnosis.
  
  
  RESULTS
  Of 134 patients, either the HER2 gene or the CEP17 signal could not be counted in 2 patients by DISH, in 1 patient by FISH method 1, and in 1 patient by FISH method 2. HER2 gene/CEP17 signal ratios were strongly correlated in DISH and FISH method 1 (R = 0.85, P < 0.05). Agreement of DISH and FISH method 1 for HER2 gene diagnosis was 98.5 % for all patients, irrespective of gene amplification (κ = 0.97). HER2 gene/CEP17 signal ratios were strongly correlated in DISH and FISH method 2 (R = 0.87, P < 0.05). Agreement of DISH and FISH method 2 for HER2 gene diagnosis was 94.1 % for gene amplification patients, 98.4 % for gene non-amplification patients, and 96.2 % for all patients (κ = 0.92).
  
  
  CONCLUSIONS
  DISH is useful for HER2 gene testing in breast cancer, and is recommended as a new option for assessing HER2 status.
authors: Division of Pathology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan, rie.horii@jfcr.or.jp.
authors: Rie
authors: R
authors: Horii
authors: Masaaki
authors: M
authors: Matsuura
authors: Takuji
authors: T
authors: Iwase
authors: Yoshinori
authors: Y
authors: Ito
authors: Futoshi
authors: F
authors: Akiyama
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D005784:Gene Amplification; D006801:Humans; D017403:In Situ Hybridization / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human