title: erb-b2 amplification by fluorescence in situ hybridization in breast cancer specimens read as 2+ in immunohistochemical analysis.
abstract: We conducted this study to ascertain the prevalence of erb-b2 gene amplification in breast cancer specimens read as 2+ in immunohistochemical analysis. Slides from patients with metastatic or recurrent breast cancer were eligible for fluorescent in situ hybridization (FISH) study if they were read as 2+ immunohistochemically for erb-b2 by a certified pathologist. The PathVysion kit (Vysis, Downers Grove, IL) was used for FISH studies. Amplification of the erb-b2 gene was defined as an erb-b2/CEP17 (chromosome 17 centromere) ratio of 2 or more in 30 tumor cells counted. From May 2003 to June 2004, 221 slides were submitted from 24 hospitals around the island. Of 216 successful hybridizations, 96 (44.4%) were determined to be erb-b2 amplified. In addition, the topoisomerase IIa gene was coamplified in 11 (21%) of 53 and deleted in 8 (15%) of 53 erb-b2 amplified cases. The erb-b2 gene amplification rate was very high in cases determined to be 2+ by immunohistochemical analysis; therefore, determination of erb-b2 status by FISH in cases scored 2+ immunohistochemically is strongly recommended.
authors.affiliation: Division of Cancer Research, National Health Research Institutes, Taipei, Taiwan.
authors.forename: Chieh
authors.initials: C
authors.lastname: Lan
authors.forename: Jacqueline Ming
authors.initials: JM
authors.lastname: Liu
authors.forename: Tsang-Wu
authors.initials: TW
authors.lastname: Liu
authors.forename: Der-Hung
authors.initials: DH
authors.lastname: Hsu
authors.forename: Suching
authors.initials: S
authors.lastname: Liang
authors.forename: Jim-Ray
authors.initials: JR
authors.lastname: Chen
authors.forename: Jacqueline Whang
authors.initials: JW
authors.lastname: Peng
mesh_terms: D000951:Antigens, Neoplasm / Q000235:genetics*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D004250:DNA Topoisomerases, Type II / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D005784:Gene Amplification; D018734:Genes, erbB-2 / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D009362:Neoplasm Metastasis / Q000235:genetics / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000235:genetics / Q000473:pathology; D011379:Prognosis; D012680:Sensitivity and Specificity; D013624:Taiwan
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D004250:DNA Topoisomerases, Type II