title: HER-2/neu in breast cancer: a comparative study between histology, immunohistochemistry, and molecular technique (FISH).
abstract: HER-2/neu is a protooncogene frequently overexpressed in breast cancer. Fluorescence in situ hybridization (FISH) is a technique targeting the gene amplification, while immunohisto-chemistry detects the protein expression. Usually both are applied to paraffin-embedded tissue. The authors studied HER-2 by FISH and immunohistochemistry (HercepTest) in 81 breast carcinomas. The results showed an overall concordance (correlation coefficient 0.64). In all cases with HercepTest score 0 and 1+, nonamplification of the gene was observed. Gene amplification was found in 20% of cases with a 2+ score and in 77.78% of cases with a 3+ score. Data described in literature for 3+ carcinomas showed a 3% to 10% discrepancy between protein expression and gene amplification, while in this study this difference was up to 22.22%. As a consequence, even if it is usually considered important to analyze only 2+ cases by FISH, 3+ scores nonamplified for HER-2/neu may be a new, interesting subset. Furthermore, the authors investigated the two-variables correlation between chromosome 17 copy number, protein over-expression, gene amplification, and presence of metastatic lymph nodes. Interesting results came from the correlation between the HercepTest score and the HER-2/neu gene amplification evaluation, HercepTest and chromosome 17 aneusomy, and gene amplification and lymph nodes status. In conclusion, the FISH technique can be an important and useful diagnostic tool to integrate the results of the HercepTest and to select patients for immunotherapy.
authors.affiliation: Department of Pathology, University of Brescia, Brescia, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Rossi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ubiali
authors.forename: Moris
authors.initials: M
authors.lastname: Cadei
authors.forename: Piera
authors.initials: P
authors.lastname: Balzarini
authors.forename: Ernestina
authors.initials: E
authors.lastname: Valagussa
authors.forename: Laura
authors.initials: L
authors.lastname: Lucini
authors.forename: Franco
authors.initials: F
authors.lastname: Alpi
authors.forename: Anna
authors.initials: A
authors.lastname: Galletti
authors.forename: Lucia
authors.initials: L
authors.lastname: Fontana
authors.forename: Chiara
authors.initials: C
authors.lastname: Tedoldi
authors.forename: Piergiovanni
authors.initials: P
authors.lastname: Grigolato
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000473:pathology; D002869:Chromosome Aberrations; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D005260:Female; D005784:Gene Amplification; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008198:Lymph Nodes / Q000473:pathology; D016133:Polymerase Chain Reaction; D011379:Prognosis; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics*; D015203:Reproducibility of Results
chemical_list: D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases